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