Turn-to-turn short protection zero-sequence impedance discriminating method for parallel reactor

A discrimination method, zero-sequence impedance technology, applied in the field of power system, can solve the problems of high proportion of inter-turn short-circuit faults, reliable operation, fault monitoring limitation, reliability of protection criteria, real-time performance and low sensitivity, and achieve stable operation Reliable, easy-to-set results

Inactive Publication Date: 2003-10-29
NANJING GUODIAN NANZI POWER GRID AUTOMATION CO LTD
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Problems solved by technology

During this process, the transient current contains rich high-order harmonics, and there is an energy exchange between the reactor and the line-to-ground capacitance. Therefore, the proportion of inter-turn short-circuit faults caused by harmonic overheating and severe micro-vibration of shunt reactors is relatively high.
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  • Turn-to-turn short protection zero-sequence impedance discriminating method for parallel reactor
  • Turn-to-turn short protection zero-sequence impedance discriminating method for parallel reactor
  • Turn-to-turn short protection zero-sequence impedance discriminating method for parallel reactor

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Embodiment Construction

[0043] The present invention will be further described below in conjunction with drawings and embodiments.

[0044] Example, Figure 6 shown.

[0045] The method for judging the zero-sequence impedance of the inter-turn short-circuit protection of the shunt reactor of the present invention is specifically implemented as follows: with an advanced and reliable hardware platform, (the schematic block diagram is shown in Figure 6 ) Use current transformers and voltage transformers to collect shunt reactors, high-side currents, low-side currents and high-side voltages, and obtain real-time currents, voltages and angles through analog / digital conversion and data processing.

[0046] Use the collected real-time current of each phase to make a weekly / weekly comparison, and the current change ΔI of the current week / week comparison i Greater than (0.1~0.3) the secondary rated current I of the reactor n , that is, it is considered that there is a disturbance in the power system, whic...

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Abstract

A zero-sequence impedance method for judging the turn-to-turn short circuit of parallelly connected reactors is disclosed. The high-end current and voltage and low-end current of said reactors are sampled. After A/D conversion and data processing, the real-time current, voltage and angle are obtained, which are compared cycle by cycle to obtain current variation. If the current variation is greater than a predefined value, disturbance exists in the electric power system. Three phase currents and three phase voltages are respectively added to obtain the zero-sequence current and zero-sequence voltage. The zero-sequence voltage is divided by the zero-sequence current to obtain a zero-sequence impedance. If the zero-sequence meets an equation, said short circuit exists.

Description

technical field [0001] The invention belongs to the field of power systems, in particular to a zero-sequence impedance discrimination method for inter-turn short-circuit protection of shunt reactors for main equipment of ultra-high voltage and ultra-high voltage (750kV) power systems. Background technique [0002] With the development of the power system, 500KV transmission lines are gradually increasing, and the ground capacitance of long-distance ultra-high voltage transmission lines is large. In order to absorb this capacitive reactive power and limit the overvoltage of the system, for lines using single-phase reclosing, In order to limit the submerged capacitor current and improve the success rate of reclosing, a three-phase-to-ground shunt reactor should be installed at both ends of the transmission line or in the substation at one end. A small reactor (or current-limiting reactor) is installed at the neutral point of the transformer, which can play the role of compensa...

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Application Information

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IPC IPC(8): G01R31/02H02H3/00
Inventor 刘效孟陈德树芮志浩王峰柳焕章
Owner NANJING GUODIAN NANZI POWER GRID AUTOMATION CO LTD
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