Flexible grounding mode power distribution network grounding fault direction algorithm

Abstract

The invention discloses a flexible grounding mode power distribution network grounding fault direction algorithm. The direction of a detection point relative to a grounding fault point is judged by utilizing the ratio of a zero-sequence measurement admittance module value before parallel resistor input to a zero-sequence measurement admittance module value after parallel resistor input at a detection point. According to the method, the fault information of the whole process before and after parallel resistor input is utilized, and when the transition resistance is relatively high, a method ofgiving the zero sequence voltage is adopted, so that the reliability of a judgment result during high-resistance grounding is improved; the method has self-ownership; the device can judge the fault direction only by utilizing the information of the position of the device; for a line with a distribution automation system, terminals simply need to upload the fault direction information; the communication pressure is small, and the matching is convenient; the terminals do not need to be subjected to accurate synchronous time synchronization; and for a distribution line without a communication condition, a fault can be removed or a fault indicator can be installed in a multistage protection time-delay cooperation mode so that line patrol efficiency is improved.

Description

technical field [0001] The invention belongs to the field of distribution network fault detection and protection, in particular to a flexible grounding mode distribution network grounding fault direction algorithm. Background technique [0002] In order to automatically extinguish the arc of most ground faults and reliably remove permanent faults, and reduce the impact of ground faults on the distribution network, China Southern Power Grid Corporation proposed a flexible grounding method in which the arc-suppression coil is connected in parallel with a small resistance, referred to as the flexible grounding method. Relevant regulations have promulgated the "Technical Specifications for Arc Suppression Coil Parallel Small Resistance Grounding Device (Draft for Comment)", and the State Grid Corporation of China is also conducting relevant demonstrations. The basic idea of ​​the flexible grounding method is to rely on the arc suppressing coil to compensate the fault current at ...

AI Technical Summary

Problems solved by technology

[0003] However, regarding the ground fault protection and treatment of flexible grounded distribution networks, there are only basic procedures given by relevant regulations, and there is still a lack of necessary theoretical analysis. Most of the on-site protection directly follows the traditional zero-sequence overcurrent protection in small resistance grounded distribution networks. , also face the problem of protection refusal to operate when the high resistance is grounded, and only use the fault information after the small resistance is put into use, and the fault characteristics of the arc-suppression coil grounding method before the small resistance is put into use are insufficient.

The control mode of arc-suppression coil parallel connection medium resistance method is similar to the flexible grounding method. It uses the difference of zero-sequence current amplitude or active component before and after the medium resistance is put into use to detect the fault line, but the fault characteristics are quite different from those of parallel connection of small resistance. method does not apply to flexible grounding

Images