Zhuhai Huawang Tech

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35kV High-Voltage Switchgear Room Partial Discharge Live Detection Case at a New Energy Plant in Guangdong, China

In May 2026, Huawang Technology received an urgent service request from a new energy industrial park in Guangdong Province. The customer reported abnormal buzzing noises coming from critical equipment inside a 35kV high-voltage switchgear room. Suspecting insulation deterioration and concerned about the impact on production safety, they requested an immediate on-site inspection.

Our engineers promptly arrived at the site with the Huawang Technology Handheld Partial Discharge Detector. Since uninterrupted power supply was essential for the plant, the inspection was carried out under energized (live) operating conditions without shutting down the equipment.

Upon arrival, our engineers first conducted a visual inspection and an initial acoustic assessment. A distinct discharge sound was clearly audible, indicating a potential insulation defect.

To accurately locate the source of the problem, we used our self-developed handheld partial discharge detector with two complementary detection methods:

Live TEV Inspection Using Huawang Technology Handheld Partial Discharge Detector

The handheld detector was first used in TEV mode to inspect the energized switchgear.

TEV Detection Results

The instrument quickly detected a significant partial discharge signal with the following measurements:

The discharge level indicated a relatively severe insulation defect. The discharge waveform was fully consistent with the abnormal buzzing sound reported by the customer, providing strong evidence of internal partial discharge activity.

Airborne Ultrasonic Partial Discharge Inspection

To further verify the diagnosis, the equipment was inspected using the detector's Airborne Ultrasonic (AA) function.

Ultrasonic Detection Results

The ultrasonic measurement recorded:Amplitude: 20.9 dBμV.The detector clearly captured ultrasonic emissions generated by the discharge, allowing our engineers to accurately confirm the fault location.

Diagnosis and Recommendations

By combining both TEV and Airborne Ultrasonic inspection methods, our engineers confirmed that the equipment was experiencing internal partial discharge. The abnormal buzzing noise was directly caused by insulation discharge activity.

A comprehensive inspection report and maintenance recommendations were provided to the customer. The plant immediately scheduled corrective maintenance, successfully eliminating the insulation defect before it could develop into a more serious equipment failure.

Project Summary

This project once again demonstrates the effectiveness of online partial discharge testing for high-voltage equipment in new energy facilities.

Compared with traditional offline inspections, live PD detection enables maintenance teams to:

Huawang Technology continues to provide professional partial discharge monitoring solutions, helping utilities and industrial customers maintain the safe and reliable operation of high-voltage electrical assets.

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GIS Partial Discharge Monitoring Project Products Successfully Shipped

Recently, a batch of products for a GIS Partial Discharge (PD) Online Monitoring Project completed final inspection and was successfully shipped from Zhuhai Huawang Technology.

The shipment includes UHF partial discharge sensors and contact acoustic emission (AE) sensors, which will be installed as part of a GIS online monitoring system. Before delivery, all products underwent factory testing, inspection, packaging, and documentation checks to ensure smooth installation and reliable operation at the project site.

Individual Testing Before Delivery

For any online monitoring system, the quality of sensor data depends on the reliability of each sensor installed in the field.

Prior to shipment, every sensor was subjected to functional testing and signal verification. Technical personnel carefully checked product performance, communication functions, interfaces, and overall condition to ensure compliance with project requirements.

After testing was completed, qualified products were arranged for packaging and final shipment preparation.

Independent Packaging and Quality Documentation

Once testing and inspection were finished, each sensor was packed individually and supplied with a factory quality certificate and related documentation.

Independent packaging helps protect products during transportation while also making inventory management and installation easier for customers upon arrival.

Afterward, all packaged units were organized into shipping cartons and secured for transportation.

UHF and Acoustic Monitoring Technologies Working Together

The project adopts a combined monitoring approach using UHF (Ultra High Frequency) sensors and contact acoustic emission sensors.

UHF sensors are used to detect electromagnetic signals generated by partial discharge activity inside GIS equipment, while acoustic sensors capture ultrasonic signals associated with insulation defects. By combining these two monitoring technologies, operators can obtain more comprehensive information about equipment insulation conditions and identify potential problems at an earlier stage.

As power utilities continue to improve asset management and equipment reliability, GIS partial discharge online monitoring has become an increasingly important tool for condition-based maintenance and preventive diagnostics.

Every Shipment Reflects Our Commitment to Quality

From production and testing to packaging and delivery, every step follows established quality control procedures.

For customers, this shipment represents another project milestone. For Zhuhai Huawang Technology, it represents a commitment to product quality and long-term reliability.

We believe that dependable monitoring results begin with dependable products. Careful testing, thorough inspection, and responsible delivery remain essential parts of every project we undertake.

The products have now been shipped and will soon arrive at the customer’s site for installation and commissioning.

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UHF and Pulse Current Partial Discharge Sensor

The UHF and Pulse Current Partial Discharge Sensor is designed for continuous online monitoring of partial discharge activity in medium- and high-voltage electrical equipment. By integrating Ultra High Frequency (UHF) detection technology with pulse current measurement, the sensor provides comprehensive insight into insulation degradation and potential defects before failures occur.

The sensor captures partial discharge signals across a frequency range of 300–1500 MHz while simultaneously measuring pulse current discharge levels up to 1500 pC. Collected data, including amplitude values, time-domain waveforms, PRPD (Phase-Resolved Partial Discharge) patterns, and PRPS (Phase-Resolved Pulse Sequence) spectra, are transmitted to the monitoring system through an RS485 communication interface.

With high sensitivity, excellent noise immunity, and reliable long-distance communication, the sensor is well suited for condition-based maintenance and predictive asset management in modern power systems.

Key Features

Real-time online partial discharge monitoring

Combined UHF and pulse current detection technology

High sensitivity for early defect detection

Strong anti-interference capability

Stable performance in harsh electrical environments

Long-distance and reliable RS485 communication

Supports waveform, PRPD, and PRPS analysis

Suitable for 24/7 continuous monitoring

Applications

Gas-Insulated Switchgear (GIS)

Medium-Voltage and High-Voltage Switchgear

Ring Main Units (RMU)

Power Transformers

Power Cable Systems

Electrical Substations

Industrial Power Distribution Networks

Technical Specifications

ParameterSpecificationUHF Frequency Range300–1500 MHzMeasurement Range0–75 dBmMeasurement Accuracy±1.5 dBAverage Effective Height≥10 mmDetection Sensitivity≤6.5 mV/m (17 dBμV/m)Dynamic Range≥40 dBPulse Current Measurement Range0–1500 pCPulse Current Accuracy±10 pCCommunication InterfaceRS485

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How Do Partial Discharge Sensors Work? UHF PD Sensor Working Principle Explained

Partial discharge (PD) is one of the earliest indicators of insulation deterioration in high-voltage electrical equipment. If left undetected, partial discharge can gradually damage insulation materials and eventually lead to equipment failure.

To identify insulation defects at an early stage, utilities and industrial facilities widely deploy partial discharge sensors as part of their condition monitoring systems.

But how do partial discharge sensors work, and why are UHF sensors becoming the preferred solution for online monitoring?

This article explains the working principle of partial discharge sensors and the role they play in modern predictive maintenance strategies.

What Is a Partial Discharge Sensor?

A partial discharge sensor is a device designed to detect physical signals generated during a partial discharge event.

When PD occurs inside electrical equipment, it produces several measurable phenomena:

Different sensor technologies capture different types of PD signals for analysis and diagnosis.

How Does Partial Discharge Occur?

Partial discharge is usually caused by insulation defects such as:

When the local electric field exceeds the dielectric strength of the insulation, a discharge occurs in a small portion of the insulation system.

Although the discharge energy is relatively low, repeated activity can significantly accelerate insulation aging.

Working Principle of UHF Partial Discharge Sensors

Among all PD detection technologies, Ultra High Frequency (UHF) monitoring is one of the most widely used methods.

Step 1: PD Generates Electromagnetic Waves

During a partial discharge event, high-frequency electromagnetic waves are emitted.

Typical frequencies range from:

300 MHz to 1500 MHz

These signals can travel through switchgear compartments, substations, and equipment enclosures.

Step 2: UHF Sensor Receives the Signal

A UHF sensor uses a specially designed antenna to capture electromagnetic waves generated by the discharge.

The received signal is converted into electrical data for further processing.

Step 3: Signal Processing

The monitoring system performs:

This helps distinguish actual PD activity from environmental interference.

Step 4: Alarm and Diagnosis

When abnormal discharge activity exceeds predefined thresholds, the monitoring platform generates alerts and maintenance recommendations.

This enables predictive maintenance rather than reactive repairs.

Advantages of UHF PD Sensors

High Sensitivity

Detects weak discharge activity at an early stage.

Excellent Noise Immunity

Less affected by industrial electromagnetic interference.

Online Monitoring Capability

Supports continuous monitoring without equipment shutdown.

Wide Coverage

A single space-mounted UHF sensor can monitor multiple pieces of equipment within a room.

Applications of Partial Discharge Sensors

Partial discharge sensors are widely used in:

GIS (Gas Insulated Switchgear)

UHF monitoring is considered the industry standard.

Switchgear

Used for insulation condition assessment.

Ring Main Units (RMU)

Supports continuous monitoring in distribution networks.

Transformer Rooms

Provides early warning of insulation defects.

Cable Systems

Detects discharge activity in cable terminations and joints.

Online Partial Discharge Monitoring Systems

Modern PD monitoring systems typically include:

Sensing Layer

Communication Layer

Platform Layer

Application Layer

Conclusion

Partial discharge sensors play a critical role in modern electrical asset management.

By detecting electromagnetic, current, acoustic, or voltage signals generated by insulation defects, these sensors provide valuable insights into equipment condition and help prevent unexpected failures.

As utilities continue to adopt predictive maintenance strategies, UHF partial discharge sensors have become one of the most effective technologies for online condition monitoring of GIS, switchgear, RMUs, transformers, and cable systems.

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How Do Partial Discharge Sensors Work? UHF PD Sensor Working Principle Explained

Partial discharge (PD) is one of the earliest indicators of insulation deterioration in high-voltage electrical equipment. If left undetected, partial discharge can gradually damage insulation materials and eventually lead to equipment failure.

To identify insulation defects at an early stage, utilities and industrial facilities widely deploy partial discharge sensors as part of their condition monitoring systems.

But how do partial discharge sensors work, and why are UHF sensors becoming the preferred solution for online monitoring?

This article explains the working principle of partial discharge sensors and the role they play in modern predictive maintenance strategies.

What Is a Partial Discharge Sensor?

A partial discharge sensor is a device designed to detect physical signals generated during a partial discharge event.

When PD occurs inside electrical equipment, it produces several measurable phenomena:

Different sensor technologies capture different types of PD signals for analysis and diagnosis.

How Does Partial Discharge Occur?

Partial discharge is usually caused by insulation defects such as:

When the local electric field exceeds the dielectric strength of the insulation, a discharge occurs in a small portion of the insulation system.

Although the discharge energy is relatively low, repeated activity can significantly accelerate insulation aging.

Working Principle of UHF Partial Discharge Sensors

Among all PD detection technologies, Ultra High Frequency (UHF) monitoring is one of the most widely used methods.

Step 1: PD Generates Electromagnetic Waves

During a partial discharge event, high-frequency electromagnetic waves are emitted.

Typical frequencies range from:

300 MHz to 1500 MHz

These signals can travel through switchgear compartments, substations, and equipment enclosures.

Step 2: UHF Sensor Receives the Signal

A UHF sensor uses a specially designed antenna to capture electromagnetic waves generated by the discharge.

The received signal is converted into electrical data for further processing.

Step 3: Signal Processing

The monitoring system performs:

This helps distinguish actual PD activity from environmental interference.

Step 4: Alarm and Diagnosis

When abnormal discharge activity exceeds predefined thresholds, the monitoring platform generates alerts and maintenance recommendations.

This enables predictive maintenance rather than reactive repairs.

Advantages of UHF PD Sensors

High Sensitivity

Detects weak discharge activity at an early stage.

Excellent Noise Immunity

Less affected by industrial electromagnetic interference.

Online Monitoring Capability

Supports continuous monitoring without equipment shutdown.

Wide Coverage

A single space-mounted UHF sensor can monitor multiple pieces of equipment within a room.

Applications of Partial Discharge Sensors

Partial discharge sensors are widely used in:

GIS (Gas Insulated Switchgear)

UHF monitoring is considered the industry standard.

Switchgear

Used for insulation condition assessment.

Ring Main Units (RMU)

Supports continuous monitoring in distribution networks.

Transformer Rooms

Provides early warning of insulation defects.

Cable Systems

Detects discharge activity in cable terminations and joints.

Online Partial Discharge Monitoring Systems

Modern PD monitoring systems typically include:

Sensing Layer

Communication Layer

Platform Layer

Application Layer

Conclusion

Partial discharge sensors play a critical role in modern electrical asset management.

By detecting electromagnetic, current, acoustic, or voltage signals generated by insulation defects, these sensors provide valuable insights into equipment condition and help prevent unexpected failures.

As utilities continue to adopt predictive maintenance strategies, UHF partial discharge sensors have become one of the most effective technologies for online condition monitoring of GIS, switchgear, RMUs, transformers, and cable systems.

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Partial Discharge Cable Testing: A Practical Approach to High Voltage Cable Reliability

High-voltage power cables are among the most critical assets in modern electrical networks. Whether installed in urban distribution systems, industrial facilities, renewable energy plants, or utility substations, cable failures can result in costly outages and safety risks.

One of the most effective methods for evaluating cable insulation health is partial discharge cable testing. By identifying early-stage insulation defects before they develop into major failures, utilities and maintenance teams can significantly improve system reliability and reduce maintenance costs.

What Is Partial Discharge in Power Cables?

Partial discharge (PD) is a localized electrical discharge that occurs when insulation begins to deteriorate. Unlike a complete insulation breakdown, PD only affects a small portion of the insulation system.

Common causes include:

Although each discharge event may be small, repeated PD activity gradually damages the insulation and can eventually lead to catastrophic cable failure.

Why Partial Discharge Cable Testing Matters

Traditional cable testing methods often identify problems only after significant insulation degradation has already occurred.

Partial discharge testing provides several advantages:

For critical power infrastructure, PD testing has become an essential component of condition-based maintenance programs.

HFCT Technology for Cable Partial Discharge Testing

One of the most widely used techniques for online PD monitoring is the High Frequency Current Transformer (HFCT) method.

HFCT sensors are installed around cable grounding conductors or cable joints without requiring direct electrical contact with the high-voltage conductor.

When a partial discharge occurs inside the cable insulation, high-frequency current pulses travel along the cable system and grounding path. HFCT sensors capture these signals and convert them into measurable data for analysis.

Key advantages of HFCT monitoring include:

Detecting Defects in Cable Joints

Field experience shows that cable accessories such as joints and terminations are often the weakest points within a cable network.

Poor workmanship, insulation contamination, or mechanical stress during installation can create conditions that lead to partial discharge activity.

By continuously monitoring PD signals around cable joints, maintenance teams can identify:

This enables corrective action before the defect develops into a service-affecting failure.

Online Monitoring vs. Periodic Testing

Traditional offline testing requires taking cables out of service, which may not always be practical for critical installations.

Online partial discharge monitoring offers several operational benefits:

As utilities move toward smart grid operations, online monitoring is becoming increasingly important.

Integrating PD Monitoring with Cable Condition Assessment

Modern cable monitoring systems combine partial discharge measurements with other diagnostic data sources.

Examples include:

When multiple data streams are analyzed together, engineers gain a more comprehensive understanding of cable health and can prioritize maintenance resources more effectively.

Applications of Partial Discharge Cable Testing

Partial discharge monitoring is widely used in:

These environments often contain critical cable assets where early fault detection is essential.

Conclusion

Partial discharge cable testing has become one of the most valuable tools for assessing the condition of high-voltage cable systems. Technologies such as HFCT-based monitoring allow utilities and industrial operators to detect insulation defects at an early stage, reducing the risk of unexpected failures and extending asset life.

As power networks continue to modernize, combining online partial discharge monitoring with intelligent data analysis will play an increasingly important role in predictive maintenance and reliable grid operation.

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Transformer Partial Discharge Analysis: Enhancing Asset Reliability with HFCT and Acoustic Emission Monitoring

Power transformers are among the most critical assets in electrical transmission and distribution networks. As transformers age, insulation degradation, moisture ingress, mechanical stress, and manufacturing defects can lead to partial discharge (PD) activity inside the equipment. If left undetected, these defects may develop into serious insulation failures, resulting in costly outages and unexpected downtime.

For utilities, industrial facilities, and renewable energy substations, transformer partial discharge analysis has become an essential part of condition-based maintenance strategies. Modern online monitoring technologies now allow operators to detect early-stage insulation defects and assess transformer health without interrupting service.

Understanding Partial Discharge in Power Transformers

Partial discharge is a localized electrical discharge that occurs within or on the surface of insulation systems under high electric stress. Although the discharge does not immediately bridge the insulation gap, repeated PD activity gradually deteriorates insulation materials and can eventually cause catastrophic failure.

Common transformer PD defects include:

Early detection and accurate diagnosis are crucial for extending transformer service life and preventing unplanned outages.

Challenges of Traditional Transformer Inspection

Conventional transformer maintenance often relies on periodic testing during scheduled outages. While these inspections provide valuable information, they cannot continuously monitor developing insulation defects.

Many PD events occur intermittently and may not be present during routine inspections. As a result, maintenance teams increasingly adopt online partial discharge monitoring systems that provide real-time visibility into transformer operating conditions.

Dual-Technology Approach for Transformer Partial Discharge Analysis

A comprehensive transformer PD monitoring solution combines multiple sensing technologies to improve detection accuracy and reduce false alarms.

High-Frequency Current Transformer (HFCT) Monitoring

HFCT sensors are installed on transformer grounding conductors to detect high-frequency pulse currents generated by partial discharge activity.

With a wide frequency response covering high-frequency PD signals, HFCT technology offers several advantages:

The sensor captures discharge pulses and converts them into diagnostic data that can be analyzed for defect identification and trend assessment.

Acoustic Emission (AE) Monitoring

While HFCT sensors detect electrical discharge signals, acoustic emission sensors capture ultrasonic waves generated by partial discharge activity and mechanical vibrations inside the transformer.

Contact-type AE sensors mounted on the transformer tank wall provide:

Because acoustic sensors directly contact the transformer surface, external noise influence is significantly reduced, improving diagnostic confidence.

Multi-Source Data Fusion Improves Diagnostic Accuracy

Using a single monitoring technology may sometimes lead to uncertainty when distinguishing actual PD activity from external noise sources.

A dual-mode monitoring architecture combines HFCT electrical measurements with acoustic emission analysis to verify discharge events from two independent perspectives.

The benefits include:

Advanced analytics can further classify typical discharge patterns such as corona discharge, floating discharge, and insulation void discharge.

Remote Online Monitoring for Smart Substations

Modern transformer monitoring systems increasingly support wireless communication architectures that simplify installation and reduce cabling costs.

HFCT and acoustic sensors can transmit monitoring data through LoRa wireless networks to local gateway nodes. The gateway then uploads data through 4G or Ethernet communication channels to centralized monitoring platforms.

This architecture enables:

The monitoring platform continuously evaluates discharge magnitude, activity trends, and transformer health status, helping maintenance teams make informed decisions before failures occur.

Applications in Modern Power Systems

Online transformer PD monitoring is widely deployed in:

By continuously tracking insulation performance, operators can move from time-based maintenance to condition-based maintenance, reducing operating costs while improving system reliability.

Supporting the Future of Transformer Asset Management

As power networks become increasingly digitalized, transformer monitoring technologies play a vital role in ensuring operational safety and asset longevity.

Solutions provided by Zhuhai Huawang Technology integrate HFCT sensors, contact-type acoustic emission sensors, intelligent analytics, and wireless communication technologies into a unified transformer monitoring platform. By combining electrical and acoustic diagnostics, operators gain deeper insight into transformer insulation health and can identify developing defects long before they become critical failures.

Conclusion

Transformer partial discharge analysis is one of the most effective methods for assessing insulation condition and preventing unexpected transformer failures. Combining HFCT and acoustic emission technologies delivers a more complete understanding of transformer health while enabling continuous online monitoring.

With real-time diagnostics, multi-source data fusion, and intelligent fault analysis, utilities and industrial operators can significantly improve asset reliability, reduce maintenance costs, and support the long-term performance of critical power infrastructure.

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Decoding Partial Discharge Activity: A Comprehensive Technical Guide for HV Engineers

Partial Discharge (PD) activity, often dubbed the "silent killer" of high-voltage (HV) assets, represents a critical phenomenon in electrical insulation systems. It is a localized dielectric breakdown of a small portion of an electrical insulation system under electrical stress, which does not completely bridge the electrodes. Instead, it occurs within voids, cracks, or interfaces within the insulation material, or on its surface, leading to gradual degradation and eventual failure of the equipment . Understanding and effectively managing PD activity is paramount for maintaining the reliability and longevity of HV infrastructure, ranging from power transformers and switchgear to cables and rotating machines.

The Physics of Partial Discharge Activity

At its core, PD is a micro-discharge phenomenon. When an insulating material is subjected to an electric field, it experiences electrical stress. If this stress exceeds the dielectric strength of a localized region within or on the surface of the insulation, a partial discharge can occur. This breakdown is not a complete flashover between conductors but rather a localized event that releases a small amount of energy. This energy manifests as light, sound (acoustic emissions), heat, and electromagnetic radiation (radio frequency signals), all of which can be detected and analyzed to diagnose the health of the insulation system.

The repetitive nature of PD activity over time causes progressive damage to the insulation. Each discharge erodes a tiny portion of the material, creating carbonized paths, further voids, and eventually leading to a complete breakdown. The rate of degradation is influenced by factors such as the magnitude and frequency of the discharges, the type of insulating material, and environmental conditions like temperature and humidity.

Classification of Partial Discharge Types

Partial discharge activity is broadly classified into several types, each with distinct characteristics and implications for insulation health. Recognizing these types is crucial for accurate diagnosis and effective mitigation strategies.

1. Internal Discharges

Internal discharges occur within voids or cavities embedded within solid or liquid insulating materials. These voids can be formed during manufacturing processes, due to thermal expansion and contraction, or as a result of aging. When the electric field across a void is higher than its breakdown strength, a discharge occurs within the gas-filled cavity. Internal discharges are particularly insidious as they are often not visible externally and can lead to significant internal degradation over time. They are a common cause of failure in power transformers and cables.

2. Surface Discharges

Surface discharges occur along the surface of an insulating material, typically at interfaces between different insulating media or between an insulator and a conductor. These discharges are often initiated by contamination, moisture, or surface irregularities that distort the electric field. Creepage discharge is a common form of surface discharge, where discharges propagate along the surface of an insulator. They can lead to tracking and flashover, especially in outdoor environments or in equipment exposed to pollutants.

3. Corona Discharges

Corona discharges occur in gaseous dielectrics, typically around sharp points or edges of conductors in air or other gases, where the electric field intensity is high enough to ionize the surrounding gas but not sufficient to cause a complete breakdown. Corona is often visible as a faint glow and audible as a hissing sound. While corona in air is generally less damaging than internal or surface discharges to solid insulation, it can produce ozone and nitric acid, which can accelerate the degradation of nearby insulating materials. In gas-insulated switchgear (GIS), corona can indicate issues with conductor surfaces or particles.

4. Electrical Treeing

Electrical treeing is a progressive breakdown phenomenon characterized by the formation of tree-like channels within solid insulation. It is often initiated by high electrical stress concentrations at defects, such as inclusions or voids, and is exacerbated by PD activity. These channels, once formed, provide pathways for further discharges, eventually leading to complete insulation failure. Treeing is a slow process but is a significant concern in polymeric insulation, such as that used in HV cables.

Impact on Asset Lifecycle

The presence of partial discharge activity significantly impacts the operational lifespan and reliability of HV assets. Initially, PD may cause minor, localized damage. However, if left unchecked, this damage accumulates, leading to a cascade of detrimental effects:

Conclusion: The Shift from Reactive to Proactive Monitoring

Historically, maintenance strategies for HV assets were often reactive, addressing failures after they occurred. However, the critical role of PD activity as a precursor to insulation failure has driven a significant shift towards proactive and predictive maintenance approaches. Modern PD monitoring systems, employing advanced sensors and data analytics, enable engineers to detect, locate, and characterize PD activity in its incipient stages. This allows for timely intervention, preventing catastrophic failures, extending asset life, and optimizing maintenance schedules. By embracing comprehensive PD monitoring, HV engineers can transition from merely reacting to failures to proactively ensuring the health and reliability of their electrical infrastructure.

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Partial Discharge Analysis in Medium-Voltage Switchgear: Methods, Sensors, and Field Applications

Partial discharge analysis has become one of the most important predictive maintenance methods for medium- and high-voltage electrical equipment. By identifying insulation degradation at an early stage, engineers can reduce unexpected outages, improve equipment reliability, and extend asset life.

Today, utilities and industrial facilities widely use portable partial discharge detection instruments to inspect:

Modern handheld devices combine multiple sensing technologies into a single platform, making field inspections faster and more accurate.

What Is Partial Discharge Analysis?

Partial discharge analysis refers to the detection, interpretation, and classification of localized electrical discharges that occur inside insulation systems.

These discharges may indicate:

If left untreated, partial discharge activity can gradually damage insulation and eventually lead to catastrophic equipment failure.

The goal of PD analysis is not only to detect discharge activity, but also to identify:

Main Technologies Used in Partial Discharge Analysis

Modern portable PD analyzers often integrate multiple detection technologies to improve diagnostic accuracy.

1. TEV (Transient Earth Voltage) Detection

TEV detection is commonly used for metal-clad switchgear inspections.

The sensor captures transient electromagnetic pulses generated by internal discharges and propagating onto the switchgear surface.

Advantages include:

Some modern instruments also support:

2. Airborne Ultrasonic Detection

Ultrasonic PD analysis is highly effective for detecting corona discharge and surface discharge in air-insulated systems.

Portable instruments may include:

Airborne ultrasonic inspection is especially useful for:

Advanced PD analyzers can also provide:

3. Contact Ultrasonic (AE) Detection

Contact ultrasonic detection is commonly applied to GIS equipment and transformer tanks.

A coupling agent is usually applied between the sensor and the equipment surface to minimize signal attenuation.

This method is sensitive to:

Many engineers prefer contact ultrasonic testing because it performs well in noisy environments.

4. HFCT (High-Frequency Current Transformer) Detection

HFCT sensors are widely used for cable and transformer grounding systems.

The sensor is clamped onto the grounding conductor to capture high-frequency current pulses generated by discharge activity.

HFCT analysis can help engineers:

Many modern instruments support both waveform and PRPD analysis in HFCT mode.

5. UHF Partial Discharge Analysis

Ultra-high-frequency detection is one of the most reliable methods for GIS partial discharge monitoring.

UHF sensors are usually installed near GIS basin insulators to capture electromagnetic signals generated by discharge activity.

Advantages include:

Some advanced portable systems provide:

PRPD Analysis in Partial Discharge Diagnostics

PRPD (Phase-Resolved Partial Discharge) analysis is one of the most important functions in modern PD instruments.

It helps engineers distinguish different defect types based on phase distribution patterns.

Typical discharge patterns include:

A well-designed PRPD system can significantly improve diagnostic efficiency during field inspections.

Intelligent Inspection Functions

New-generation handheld analyzers increasingly support intelligent inspection workflows.

Typical functions include:

These functions improve inspection efficiency for large substations and utility networks.

Some manufacturers, including Zhuhai Huawang Technology, have integrated multi-sensor PD analysis and intelligent inspection management into portable field devices.

Conclusion

Partial discharge analysis plays a critical role in modern condition-based maintenance strategies.

By combining:

engineers can detect insulation defects earlier and make more informed maintenance decisions.

As substations become more intelligent and asset reliability requirements continue increasing, portable multi-function partial discharge analyzers are becoming essential tools for electrical maintenance teams.

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Partial Discharge and Corona Detection in High Voltage Equipment: Why Multi-Technology Inspection Matters

In modern substations and industrial power systems, insulation failure rarely happens without warning. Before a major breakdown occurs, electrical assets often produce early symptoms such as partial discharge (PD), corona activity, ultrasonic noise, or transient electromagnetic pulses. Detecting these warning signs early is critical for preventing outages and reducing maintenance costs.

This is why partial discharge and corona detection has become an essential part of predictive maintenance programs for utilities, switchgear manufacturers, and industrial facilities.

A new generation of handheld diagnostic instruments now combines multiple sensing technologies into one portable platform, allowing engineers to perform fast on-site inspections across different types of high-voltage equipment.

What Is Partial Discharge and Corona Detection?

Partial discharge refers to localized electrical discharges that only partially bridge insulation between conductors. Corona discharge is a related phenomenon caused by ionization around high electric field regions, often occurring near sharp conductors or insulation defects.

These issues can appear in:

If left undetected, partial discharge can gradually damage insulation and eventually lead to catastrophic equipment failure.

Corona activity may initially seem less severe, but prolonged exposure can still accelerate insulation aging, increase energy loss, and generate electromagnetic interference.

Why Traditional Single-Method Detection Is No Longer Enough

Many older inspection tools rely on only one sensing method. However, different equipment types and defect modes generate different signal characteristics.

For example:

Because of this, modern maintenance teams increasingly prefer integrated instruments capable of combining several detection technologies within a single device.

Multi-Technology Detection Improves Accuracy

According to the multifunction handheld partial discharge detector manual, the instrument supports multiple diagnostic methods including:

The system also supports waveform analysis modes such as:

These functions help engineers distinguish actual discharge activity from environmental interference.

TEV Detection for Switchgear Inspection

TEV technology is widely used for medium-voltage switchgear partial discharge inspection.

The manual describes TEV testing as a built-in function where the sensor is placed directly against the inspection point without additional wiring.

This approach allows maintenance personnel to quickly scan metal-clad switchgear panels during energized operation.

Ultrasonic Detection for Corona and Airborne Discharge

Corona discharge often generates airborne ultrasonic signals before visible damage occurs.

The handheld detector supports both built-in and external airborne ultrasonic sensors for corona detection applications. The manual notes that directional ultrasonic probes can be used for switchgear rooms and overhead line inspection.

This is particularly useful for:

UHF Detection for GIS Partial Discharge Monitoring

Gas-insulated switchgear (GIS) requires highly sensitive detection methods because internal defects are often enclosed within sealed metal chambers.

The instrument manual explains that the UHF sensor is mounted near the GIS basin insulator to capture ultra-high-frequency discharge signals.

UHF detection is highly effective for identifying:

PRPD Analysis Helps Identify Defect Types

One of the most valuable functions in modern PD analysis is PRPD (Phase Resolved Partial Discharge) spectrum analysis.

The manual describes PRPD graphs as displaying discharge amplitude variation across the 360-degree phase cycle.

This analysis helps engineers distinguish between:

Accurate defect classification allows maintenance teams to prioritize critical assets before insulation failure develops.

Intelligent Inspection Features Improve Field Efficiency

Beyond signal acquisition, modern handheld PD instruments are increasingly designed for intelligent inspection workflows.

The manual includes features such as:

These functions help standardize field inspection procedures and simplify long-term trend analysis.

For utilities managing large substations, intelligent inspection capability can significantly improve maintenance efficiency.

Portable Partial Discharge and Corona Detection for Modern Utilities

As substations become more digitalized and maintenance strategies shift toward predictive diagnostics, portable multi-function PD detectors are becoming standard tools for field engineers.

Compared with single-function instruments, integrated handheld systems provide:

Companies such as Zhuhai Huawang Technology are developing portable partial discharge and corona detection solutions for switchgear, GIS, transformers, cables, and overhead power systems.

For utilities and industrial maintenance teams, early detection remains the most effective way to avoid costly unplanned outages.

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Ultrasonic Inspection Devices Ready for Power Equipment Inspection Projects

Zhuhai Huawang has recently completed the shipment of a batch of ultrasonic inspection devices for power equipment inspection applications.

As power systems continue to expand, utilities are placing greater emphasis on preventive maintenance and live-line inspection. Equipment such as switchgear, transmission lines, ring main units, and substations may gradually develop insulation aging, loose connections, or partial discharge problems during long-term operation. Early detection has become increasingly important for maintaining stable and reliable power supply.

Ultrasonic inspection devices are widely used in the power industry for detecting abnormal discharge signals without shutting down equipment. By capturing ultrasonic signals generated by electrical faults, inspectors can quickly identify hidden risks and locate potential defect points in the field.

The ultrasonic inspection device shipped by Zhuhai Huawang adopts a non-contact live-line detection method with an effective inspection distance of up to 30 meters. This allows inspection personnel to carry out safe testing while electrical equipment remains energized.

The device supports real-time audio, waveform, and dB value output, helping engineers analyze equipment conditions more efficiently during inspection work. Its lightweight and portable design also makes it suitable for outdoor field applications and routine maintenance tasks.

Typical applications include:

Compared with traditional manual inspection methods, ultrasonic detection technology improves inspection efficiency and helps maintenance teams discover hidden defects earlier before failures occur.

Zhuhai Huawang has been focusing on power equipment condition monitoring and partial discharge detection solutions for many years. The company provides a range of products including online partial discharge monitoring systems, ultrasonic inspection devices, UHF sensors, wireless temperature monitoring systems, and intelligent power maintenance solutions.

With growing demand for smart power maintenance and condition-based monitoring, Zhuhai Huawang continues to improve product reliability and field application performance to support safer and more efficient power system operation worldwide.

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Switchgear Partial Discharge Online Monitoring System Shipment | 4-in-1 PD Sensor Project Case

Recently, Huawang successfully completed the shipment of a switchgear partial discharge and temperature online monitoring project for power equipment condition monitoring applications.

The project includes:

The system is designed to provide real-time monitoring of partial discharge activity, equipment temperature, and environmental conditions, helping improve the safety and reliability of power systems.

4-in-1 Partial Discharge Sensor for Comprehensive Monitoring

The core device used in this project is the 4-in-1 partial discharge sensor, integrating:

Compared with conventional single-parameter monitoring solutions, the multi-technology integrated design enables more accurate fault identification and insulation condition assessment.

The solution is widely used for:

Why Online Partial Discharge Monitoring Matters

Partial discharge is one of the earliest indicators of insulation deterioration in electrical equipment.

If not detected in time, it may lead to:

As smart grid technologies continue to develop, more substations and industrial facilities are deploying online partial discharge monitoring systems to achieve predictive maintenance and reduce operational risks.

Key Features of the Monitoring System

Multi-Parameter Integrated Detection

The system simultaneously collects:

This helps maintenance teams better evaluate equipment operating conditions.

Intelligent Alarm and Diagnosis

Built-in intelligent algorithms analyze:

The system automatically generates alarms when abnormal conditions are detected.

Strong Anti-Interference Capability

To ensure stable operation in complex substation environments, the system adopts:

This significantly improves monitoring accuracy and reliability.

Remote Online Monitoring

With the IoT concentrator, monitoring data can be uploaded to the cloud platform in real time.

Operators can remotely access:

through PC or mobile devices.

Easy Installation

The system supports:

This reduces installation time and operational impact.

Power Equipment Monitoring Solutions

As a manufacturer specializing in power equipment condition monitoring,Huwang focuses on:

Its products and monitoring systems have been applied in:

helping customers improve equipment reliability and digital operation management.

Conclusion

With the continuous development of smart substations and intelligent power systems, online partial discharge monitoring is becoming increasingly important for predictive maintenance.

The successful shipment of this switchgear monitoring project further demonstrates the value of 4-in-1 partial discharge sensors in modern power equipment monitoring applications.

Huawang will continue providing reliable and intelligent monitoring solutions for global power industry customers.

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Switchgear Partial Discharge Online Monitoring System real installation!

Zhuhai Huawang Tech high-frequency current sensors installed on cable terminal heads and grounding lines. IoT concentrator enables real-time PD data collection.

High sensitivity • Wide frequency (0.1–100MHz) • Strong anti-interference • Non-intrusive installation

Early warning for switchgear insulation faults! ⚡

More info: www.huwor.net

#SwitchgearPD #PartialDischarge #PDMonitoring #HighFrequencySensor #SmartGrid #ElectricalEngineering

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Ring Main Unit Online Monitoring System Solution for Distribution Networks

1. Industry Background

In modern distribution networks, the ring main unit (RMU) plays a critical role in power distribution, network interconnection, and load transfer within 10kV systems. With the rapid expansion of urban power grids, the number of RMUs continues to grow, often operating under high load conditions in enclosed environments.

Over time, insulation degradation, loose connections, and environmental factors can lead to partial discharge, abnormal temperature rise, and even unexpected outages. These issues are often difficult to detect at an early stage.

Traditional maintenance methods rely heavily on periodic manual inspections, which are limited by long intervals and lack real-time visibility. Early-stage faults—especially partial discharge and contact overheating—typically show no obvious external signs, making proactive detection a challenge.

2. System Architecture

The ring main unit online monitoring system adopts a multi-source sensing architecture, integrating:

The system consists of:

By combining edge computing with cloud-based analytics, the system forms a complete loop of data acquisition, analysis, and remote operation.

3. Core Monitoring Functions

3.1 Partial Discharge Monitoring for RMU

The system utilizes both UHF (Ultra High Frequency) sensors and HFCT (High-Frequency Current Transformer) sensors to detect partial discharge signals from different propagation paths.

This dual-detection approach improves sensitivity and noise immunity, enabling early identification of insulation defects, surface discharge, and poor contact conditions.

3.2 Wireless Temperature Monitoring

Wireless temperature sensors are installed at key points such as cable joints, busbar connections, and switch contacts.

Powered by inductive energy harvesting, these sensors require no external wiring and support long-term stable operation. Continuous temperature tracking helps identify:

Trend analysis allows early warning before critical overheating occurs.

3.3 Environmental Monitoring

Temperature and humidity inside RMUs significantly affect insulation performance.

The system monitors environmental conditions in real time to detect:

By correlating environmental data with partial discharge and temperature trends, the system enhances diagnostic accuracy.

4. Intelligent Analysis and Early Warning

The system performs preliminary data processing at the edge level, reducing unnecessary data transmission and improving response efficiency.

The central platform applies advanced analytics, including:

When thresholds are exceeded or abnormal trends are detected, alerts are triggered automatically via platform notifications or messaging systems.

5. Key Benefits

Deploying a ring main unit monitoring system provides:

It enables a shift from reactive maintenance to predictive maintenance in distribution networks.

6. Applications

The system is suitable for:

Its modular design allows flexible installation with minimal impact on existing equipment, making it ideal for both new installations and retrofit projects.

7. Conclusion

As distribution networks evolve toward digitalization and intelligent operation, online monitoring of ring main units becomes essential. By integrating partial discharge monitoring, temperature sensing, and environmental analysis, this solution provides a reliable foundation for safer and smarter power system operation.

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Partial Discharge Sensor in GIS: 110kV Substation Online Monitoring Project in Xinjiang

1. Project Background: Safeguarding GIS Insulation in Harsh Conditions

Xinjiang is known for its extreme climate—large temperature fluctuations between day and night, low humidity, and frequent environmental stress. These conditions place significant demands on the sealing performance and insulation reliability of Gas Insulated Switchgear (GIS) in 110kV substations.

Traditional periodic inspections often fail to capture intermittent or early-stage partial discharge (PD) activity. To enhance operational reliability and prevent unexpected failures, Zhuhai Huawang Technology was commissioned to implement a comprehensive online GIS partial discharge monitoring system.

2. Technical Deployment: UHF-Based Partial Discharge Sensor in GIS

In this project, high-sensitivity UHF partial discharge sensors were strategically installed at key positions within the GIS, based on equipment structure and field conditions.

Anti-Interference Capability

The electromagnetic environment on site is complex. By applying advanced filtering algorithms, the system effectively suppresses interference from mobile communication signals and ambient electromagnetic noise, ensuring accurate PD detection.

Real-Time Monitoring

The partial discharge sensor in GIS captures weak UHF signals generated by insulation defects. These signals are transmitted via low-loss coaxial cables to a centralized monitoring unit installed at the substation.

Intelligent Data Analysis

The system automatically generates PRPD (Phase Resolved Partial Discharge) and PRPS (Phase Resolved Pulse Sequence) patterns. These visual tools allow maintenance personnel to quickly identify discharge types and assess insulation conditions.

3. On-Site Implementation

The sensors were installed without disrupting normal substation operation. The compact design and flexible mounting options of the UHF sensors ensured seamless integration with existing GIS equipment.

Field deployment confirmed stable signal acquisition, even under harsh environmental conditions typical of Xinjiang.

4. Project Results and Customer Value

From Reactive Maintenance to Predictive Monitoring

The system enables 24/7 continuous monitoring, replacing reliance on manual inspection and significantly improving fault detection efficiency.

Accurate Fault Localization

With multi-channel synchronous triggering, the system can estimate the location of partial discharge sources based on signal time differences, helping maintenance teams act quickly and precisely.

Proven Reliability in Harsh Environments

The monitoring system has demonstrated stable operation despite extreme temperature variations and dry conditions. All performance indicators meet the requirements of industry standard DL/T 1512.

Conclusion

This project highlights how deploying a reliable partial discharge sensor in GIS can significantly enhance the safety and stability of high-voltage substations. By combining UHF detection technology with intelligent data analysis, utilities can shift from reactive maintenance to proactive asset management—especially in challenging environments like Xinjiang.

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Partial Discharge Detector Price Guide: Cost, Types & How to Choose the Right Supplier

Partial discharge (PD) detection is essential for maintaining the safety and reliability of high-voltage electrical equipment such as switchgear, GIS, transformers, and power cables.

One of the most searched questions by engineers and procurement managers is: 👉 “What is the price of a partial discharge detector?”

This guide provides a clear breakdown of pricing, influencing factors, and trusted manufacturers in the market.

💰 What Is the Price of a Partial Discharge Detector?

The price of a partial discharge detector depends on its type and functionality.

Typical price ranges:

👉 Portable devices are suitable for routine inspections, while online systems provide continuous monitoring and early warning.

⚙️ What Affects Partial Discharge Detector Price?

1. Detection Technology

Different PD detection methods impact pricing:

👉 Devices integrating multiple technologies are more expensive but significantly more accurate.

2. Application Scenario

Complex systems require higher-performance sensors and algorithms.

3. Portable vs Online Monitoring

4. Software & Intelligence Level

Advanced systems may include:

These features increase cost but improve diagnostic efficiency.

🏭 Top Partial Discharge Detector Manufacturers

When evaluating suppliers, buyers often compare multiple global and regional manufacturers.

Some commonly referenced companies include:

In addition, emerging manufacturers such as Zhuhai Huawang Technology provide cost-effective solutions with multi-technology integration and flexible customization for different applications.

👉 Choosing the right supplier depends on budget, application, and required features.

🧠 How to Choose the Right PD Detector

✔ Based on Equipment

✔ Based on Usage

✔ Based on Budget

Lower-cost devices may lack sensitivity, while high-end systems provide long-term reliability and better diagnostics.

❗ Why Cheap PD Detectors Can Cost More

Many buyers focus only on price, but low-cost devices often result in:

👉 Investing in a reliable PD detector reduces long-term operational costs.

📊 Quick Comparison: Portable vs Online PD Systems

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Advanced Partial Discharge Detection Equipment: HMJ9001-QW Wireless Solution

In the realm of high-voltage electrical infrastructure, maintaining the integrity of insulation is paramount for ensuring reliability, safety, and operational longevity. Partial discharge (PD) is a localized dielectric breakdown of a small portion of an electrical insulation system under high voltage stress, which does not completely bridge the gap between two conductors. It is a critical early indicator of insulation degradation, often preceding catastrophic equipment failure if left undetected. Traditional PD detection methods can be cumbersome, time-consuming, and often require equipment shutdown, posing significant challenges for continuous monitoring and predictive maintenance strategies.

The Imperative for Modern Partial Discharge Detection Equipment

The evolution of electrical grids demands more efficient, accurate, and non-intrusive methods for assessing the health of high-voltage assets. This is where advanced partial discharge detection equipment like the HMJ9001-QW emerges as a game-changer. Designed to overcome the limitations of conventional systems, the HMJ9001-QW offers a sophisticated, wireless solution for comprehensive PD monitoring across a wide range of electrical apparatus.

HMJ9001-QW: Redefining Wireless PD Monitoring

The HMJ9001-QW is a state-of-the-art wireless multifunctional partial discharge detector that integrates multiple advanced sensing technologies. This innovative device allows for non-intrusive, online monitoring of partial discharges in critical assets such as switchgear, ring main units, Gas Insulated Switchgear (GIS), cables, and transformers. Its wireless capabilities ensure flexibility and safety, enabling technicians to perform diagnostics in complex and hazardous environments without direct contact or service interruption.

Multi-Sensor Fusion for Comprehensive Diagnostics

One of the HMJ9001-QW's most significant advantages is its multi-sensor fusion capability. It combines several detection principles to provide a holistic view of PD activity, enhancing accuracy and diagnostic precision. The integrated sensors include:

This combination allows the HMJ9001-QW to capture a broader spectrum of PD phenomena, making it highly effective in identifying various types of insulation defects.

Wireless Connectivity and Intelligent Analysis

The HMJ9001-QW leverages advanced wireless communication technologies, including Wi-Fi and Bluetooth, to transmit real-time data to an Android-based smartphone or tablet. This eliminates the need for cumbersome cables, enhancing operational safety and convenience. The dedicated mobile application provides powerful analytical tools, allowing users to:

Intuitive Alarms and Robust Design

Equipped with an intuitive alarm system, the HMJ9001-QW provides immediate feedback on the severity of partial discharges using a clear red, yellow, and green indicator light system. This allows for quick assessment and prioritization of maintenance actions. The device is designed for durability and reliability in challenging field conditions, featuring an embedded Linux/Android operating system and robust communication options including USB, Wi-Fi, Bluetooth, and NFC.

Applications Across the Electrical Grid

The versatility of the HMJ9001-QW makes it an indispensable tool for various applications in electrical asset management:

Key Technical Specifications

Conclusion

The HMJ9001-QW wireless multifunctional partial discharge detector represents a significant leap forward in electrical asset monitoring. By combining multi-sensor technology, wireless convenience, and intelligent data analysis, it empowers maintenance teams to conduct predictive maintenance with unprecedented efficiency and accuracy. Investing in such advanced partial discharge detection equipment is not just about preventing failures; it's about optimizing operational costs, enhancing safety, and ensuring the long-term reliability of critical electrical infrastructure. Embrace the future of electrical diagnostics with the HMJ9001-QW and safeguard your assets against unforeseen breakdowns.