Flexible grounding mode power distribution network grounding fault direction algorithm

A grounding fault and grounding method technology, applied in the fault location, detecting faults according to the conductor type, measuring electricity and other directions, can solve the problems such as the protection method is not suitable for flexible grounding methods, insufficient utilization of fault characteristics, and difference in fault characteristics, etc. Line efficiency, high resistance to transition resistance, and low communication stress

CN111537838APending Publication Date: 2020-08-14CHINA UNIV OF PETROLEUM (EAST CHINA)
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-08-14

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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.
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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 ...

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Embodiment Construction

[0020] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0021] A flexible grounding method distribution network grounding direction algorithm, its fault direction identification process is as follows figure 1 As shown, the details are as follows:

[0022] Step 1: Start the device, measure the effective value of zero-sequence voltage and zero-sequence current in the current period, and calculate the admittance modulus value of zero-sequence measurement, and store it in Y 1 ;

[0023] Step 2: Measure the effective value of the zero-sequence voltage and the effective value of the zero-sequence current in the next cycle, if the effective value of the zero-sequence voltage is not less than U set (this embodiment takes 120V), further calculate the zero-sequence measurement admittance, and store it in Y 2 , go to step 4; otherwise, go to step 3;

[0024] Step 3: If the effective value of the zero-seq...