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P Type Current Transformer Saturation Method

1. Minimize the current transformer secondary load resistance. Increase the cable cross-section if necessary. 2. Use "PR" type current transformers . This type of transformer provides a limit on the remanence of the standard, that is not more than 10%. At present, some manufacturers of protective devices on the saturation of the current transformer to take a number of ways, one of which is in the saturation before they have to determine the type of failure and failure in the area. Such as Nurui relay protection company RCS-915 and Shenzhen Nairi BP-2B and so on. Saturation always has a process that fixes the nature of the fault before the CT is not saturated. At this point, the current transformer is saturated, can not affect the protection action. About "TPY" current transformers of dc current transformers manufacturer . For the relay protection of the 500kV system, this type of current transformer has a small air gap in its core. Anti-transient saturation ability, the requirements of the core remanence is less than 10%. "TPY" current transformer in the current North China 500kV power system is very common. Mainly used for line, transformer main protection. However, the "TPY" current transformer in a serious short circuit, the remanence of the attenuation is slower, longer delay, for some protection does not apply. Such as: failure to protect the current identification components. Due to residual magnetic attenuation slow, resulting in the return of the current component is bound to be slow, in order to prevent false start failure protection, protection of the current component can not use "TPY" type current transformer, still use "P" type current transformer. This point, the design must be considered. The above mentioned voltage transformer and current transformer characteristics, are the adverse effects of relay protection, to make our relay protection device can be safe and reliable operation, we must understand these. Such as: high-voltage transmission line backup distance protection, is the use of current increases and the characteristics of the voltage drop to determine the fault, but because the fault began, the voltage can not be quickly decay, the protection can not move quickly, when the voltage attenuation to protection can start , The current transformer is saturated, and ultimately may lead to protection can not correct action. The current widely used optical fiber differential protection, the use of a single analog to determine the fault, the situation is much better, combined with the protection of the nature of the fault quickly determine the function, you can reliably ensure rapid removal of the fault. more transformer in www.xp-elec.com

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The Structure And Principle Of Audio Transformer

Audio frequency transformer and high-frequency transformer characteristic parameter 1, the frequency response Refers to the audio toroidal transformer secondary output voltage characteristics with the operating frequency changes. 2, pass the band If the transformer output voltage in the middle frequency is U0, when the output voltage (input voltage remains unchanged) down to 0.707U0 when the frequency range, known as the transformer pass band B. 3, the initial and secondary impedance ratio toroidal transformers for audio initial and secondary access to the appropriate impedance Ro and Ri, the transformer primary and secondary impedance matching, then the ratio of Ro and Ri as the primary, secondary impedance ratio. In the case of impedance matching, the transformer work in the best condition, the highest transmission efficiency. Characteristics of power transformers 1, the operating frequency Transformer core loss and frequency of a great relationship, it should be based on the use of frequency to design and use, this frequency, said operating frequency. 2, rated power At the specified frequency and voltage, the transformer can work long-term, without exceeding the specified temperature rise of the output power. 3, rated voltage Refers to the transformer coil to allow the voltage applied, the work shall not exceed the specified value. 4, the voltage ratio Refers to the transformer primary voltage and secondary voltage ratio, there is no-load voltage ratio and the difference between the load voltage ratio. 5, no-load current Transformer secondary open, the primary still have a certain current, this part of the current is called no-load current. The no-load current consists of a magnetizing current (generating flux) and an iron loss current (caused by core loss). For 50 Hz power transformers, the no-load current is essentially equal to the magnetizing current. more transformer in www.xp-elec.com

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Audio transformer

In radio communication, radio and television, automatic control as a voltage amplification, power output circuit components. The frequency response of audio toroidal transformer is uniform in the working frequency band. Its core is made of high permeability magnetic material. The coupling of the primary winding and the secondary winding is close, so the magnetic flux passing through the primary winding is nearly all linked with the secondary winding. The lowest frequency of the passband is determined by the original winding inductance, and the highest frequency is determined by the leakage inductance of the transformer. To ensure that the transformer has sufficient frequency band, the original winding inductance should be large, leakage inductance should be small. Hysteresis loss of the core and magnetic saturation will cause signal distortion. Appropriate configuration of the load, increase the load current, can reduce the impact of hysteresis loss; increase core section, leaving the air gap, the magnetic circuit can not be saturated, this can reduce the signal distortion. toroidal transformers for audio are classified into three categories according to their position in the electronic circuit. Connected between the output circuit and the load is called the output transformer; Connected between the source and the amplifier input is called the input transformer; Connected to the output circuit in the next level and the next level between the input circuit is called interstage transformer. Should pay attention to before and after the use of the impedance matching, to avoid the signal distortion caused by reflection. In order to get the maximum load power, load impedance through the output transformer impedance, after conversion should be the same power amplifier level of the same impedance, not too large nor too small. Audio signal amplified by the audio transformer, the voltage can be large, but the power loss due to loss of the transformer has been reduced. In this way, it can not drive a large load. So the audio transformer can not replace the electronic audio signal amplifier. more transformer in www.xp-elec.com

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What Are The Advantages Of Electronic Current Transformer?

1. High and low voltage completely isolated, high security, with excellent insulation properties, does not contain iron core, eliminating the magnetic saturation and ferroresonance and other issues. current transformers due to the use of the core, there are inevitably magnetic saturation and ferromagnetic resonance problems. Unconventional transformer in principle with the traditional transformer has an essential difference, generally do not do magnetic core coupling, thus eliminating the magnetic saturation and ferromagnetic resonance phenomenon, so that transient operation of the transformer is good, good stability, to ensure The system is running high reliability. 2. Anti-electromagnetic interference performance, low-pressure side of the risk of open-circuit high-pressure. Electromagnetic current transformer of current transformers manufacturers secondary circuit can not open the road, low-pressure side there is open danger. There are only fiber-optic links between the high-voltage side and the low-voltage side of the non-conventional transformer. The signal is transmitted through the optical fiber. The high-voltage circuit and the secondary circuit are completely isolated electrically. The mutual inductor has good anti-electromagnetic interference ability. Of the high-voltage danger. 3. Dynamic range, high accuracy, wide frequency response range 4. Data transmission anti-interference ability. 5. Not due to oil-filled and potentially flammable, explosive and other dangerous letter unconventional transformer insulation structure is relatively simple, generally do not use oil as an insulating medium, will not cause fire and explosion hazards. 6 small size, light weight Non-conventional transformer core, the weight of the same voltage level than the electromagnetic transformer is much smaller. More transformer and inductor in www.xp-elec.com

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The Differences Between High-frequency Transformer And Inductor

High-frequency transformers and inductors the same place: high-frequency transformers and inductors are wrapped with enameled wire package, the internal core or core. High-frequency transformers and inductors different places: Transformer is mainly used for voltage conversion, which is based on the law of electromagnetic induction. choke coils is generally used in electronic circuits, according to Lenz's law. The former generally has two or three windings, primary and secondary windings, for the step-up transformer, the primary winding turns less diameter thicker, secondary winding turns and fine wire diameter, step-down transformer with On the contrary, the primary turns number of small diameter, small number of secondary turns small diameter, widely used in a variety of electrical appliances as a power source. Transformer is the exchange of voltage, current and impedance devices, when the primary coil with AC current, the core (or core) will produce AC magnetic flux, the secondary coil induces a voltage (or current). Transformer from the core (or core) and the common mode choke coil , the coil has two or more windings, which access the power supply winding called the primary coil, the rest of the winding is called the secondary coil. Inductance coil is the use of electromagnetic induction principle of the work of the device. When a current flows through a wire, it will be around the wire in a certain electromagnetic field, and the electromagnetic field of the wire itself will be in the electromagnetic field within the induction of the wire effect. more inductors and transformer in www.xp-elec.com

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Do You Know These Things About Common Mode Choke?

Common mode inductors, also known as common mode chokes  are symmetrically wound in a closed magnetic ring in the opposite direction, the same number of turns of the coil. An ideal common mode choke suppresses the common-mode interference between L (or N) and E, while the non-inductive suppression of the differential mode interference between L and N occurs. But the actual coil winding system is not fully symmetrical lead to differential mode leakage inductance. The signal current or supply current flows in opposite directions in the two windings, the magnetic fluxes generated cancel each other out, and the choke coil exhibits a low impedance. Common-mode noise current (including the ground loop caused by the harassment current, also called vertical current) flows through the two windings in the same direction, the magnetic flux generated in the same direction, the choke appears high impedance, thereby inhibiting a total of Mode noise. Common mode inductor is essentially a two-way filter: on the one hand to filter out common-mode electromagnetic interference on the signal line, on the other hand they do not suppress their own outward electromagnetic interference, to avoid affecting the same electromagnetic environment, the normal operation of other electronic equipment . The common-mode choke can transmit differential-mode signals that can pass both DC and low-frequency differential-mode signals, and exhibit high impedance for high-frequency common-mode noise, so it can be used to suppress common-mode current disturbances. Common mode choke coils is the switching power supply, inverter, UPS power supply and other equipment in an important part. Its working principle: When the operating current flows through the two opposite coil, resulting in two mutually canceling magnetic field H1, H2, at this time mainly by the operating current coil Ohm resistance and negligible operating frequency of the small leakage inductance damping . If there is interference signal flow through the coil, the coil that presents a high impedance, resulting in a strong damping effect, to the role of attenuation interference signal. The common-mode choke insertion loss characteristic is measured by its impedance characteristic in the interference spectrum. When the frequency range of 0.01 ~ 1MHZ, the impedance depends on the coil inductance L. When the frequency range of 1 ~ 10MHZ, the impedance depends on the winding distributed capacitance CK. When the frequency range> 10MHZ, the impedance and winding capacitance, the main circuit inductance, leakage inductance and core loss of iron and copper losses formed by the parallel circuit (ZS is the equivalent impedance). www.xp-elec.com will be your reliable partner for inductor chokes.

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UF / UU Series Common Mode Inductors

Material: basically ferrite, of course, this ferrite also have distinction, generally have MXO - manganese zinc and NXO - nickel zinc type. The main advantages of nickel-zinc type: initial permeability low (less than 1000u), but can work at a relatively high frequency (greater than 100MHZ), to maintain the same permeability. Very strong very great. NXO has higher resistivity than MXO. The use of ferrite for high-frequency common mode chokes  similar to the role of damping the high-frequency clutter to thermal energy released, which explains the common-mode inductor temperature. Baidu on the principle of common mode inductor than I know: two coils wound on the same core, the number of turns and phase are the same (wound reverse). In this way, when the normal current in the circuit flows through the common mode inductor, the current in the same phase winding inductance coil in the reverse magnetic field cancel each other, then the normal signal current is mainly affected by coil resistance (and a small amount due to leakage When the current flowing through the coil with a common mode interference, the coil will produce the same magnetic field and increase the inductance of the coil, so that the performance of high-impedance coil, resulting in a strong damping effect to This attenuation of common-mode current, to achieve the purpose of filtering. Overall advantage: The most important point: low cost (I use this is 0.9 yuan), you can use the PFC inductors  around, efficient, commonly used UU9.8 or UU10.5; A skeleton, winding process should be better control, you can do a higher inductance; Good for voltage and reliability? Good plug-in, good installation. Four feet Well, no holes on the point of the problem; basic small current in the power supply, because the diameter can not be very thick, so the current can not be too large; Overall disadvantage: Spatial factors: the location of the package, maybe because it is relatively strong, unlike the magnetic ring so small and exquisite; More serious heat, but also according to my measured: 90V input full load at room temperature, you can fast to 90 degrees; Application: Generally used in cost control more stringent, or small power applications. more inductors in www.xp-elec.com