Method and system for carrying out transient and intermittent earth fault detection and direction determination in three-phase medium-voltage distribution system

A technology of power distribution system and transient direction, applied in the direction of electric power measurement through current/voltage, fault location, information technology support system, etc., can solve the problem that conventional protection equipment cannot detect, cannot give accurate results, and limit faults Event duration etc.

Inactive Publication Date: 2010-10-13
AREVA T& D UK +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Thus, the impedance in the fault circuit limits the fault current below the threshold of the fault detector, or the conduction of the transient limits the duration of the fault event and makes it undetectable to conventional protection equipment
Although these faults may not cause serious damage to the system, they expose imperfections in the feeder: the intermittent conduction of transient faults can be a signal of degraded insulation conditions on the line or cable
Therefore, when the conventional phasor-based method is used for direction detection, it cannot give accurate results

Method used

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  • Method and system for carrying out transient and intermittent earth fault detection and direction determination in three-phase medium-voltage distribution system
  • Method and system for carrying out transient and intermittent earth fault detection and direction determination in three-phase medium-voltage distribution system
  • Method and system for carrying out transient and intermittent earth fault detection and direction determination in three-phase medium-voltage distribution system

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Embodiment Construction

[0068] Such as figure 1 As shown, the system of the present invention is suitable for detecting transient / intermittent single-phase ground faults in a three-phase three-wire medium voltage (10kv-35kv) power distribution system. In order to selectively alarm a faulted feeder among all feeders 10 radially connected to the bus 11, the neutral point of the system is not grounded or is grounded only at one point 16, often in the substation where the voltage is transformed. The detection device 12 is usually installed in a substation where a busbar is installed, and the detection device 12 samples the residual current from a CT (current transformer) 13 on one feeder and the residual voltage from a PT (voltage transformer) 14 on the busbar. It detects a transient earth fault event 15 and identifies the direction of the event. Direction results are forward (from busbar to feeder) and reverse (from feeder to busbar). When the fault occurs on the feeder on which the detector has been ...

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Abstract

The invention relates to a method and a system for carrying out transient and intermittent earth fault detection and direction determination in a three-phase medium-voltage distribution system comprising a plurality of circuits. The system comprises a sampling unit for sampling residual currents and residual voltages on the circuits, a transient direction detection unit based on the instantaneous power, a random intermittent detection unit based on the intermittent change of the magnitude of the residual current, an integrated transient direction detection and random intermittent detection unit, and an alarm unit for indicating the inspection of the status of a circuit.

Description

technical field [0001] The present invention relates to a method and system for transient and intermittent earth fault detection and direction determination in a three-phase medium voltage distribution system. Background technique [0002] The technical field is power system protection and control. The invention relates to transient / intermittent single-phase ground fault detection and ground fault direction determination in a three-phase medium voltage (10kv-35kv) power distribution system. A transient event refers to a short-term disturbance lasting only one power cycle or within several power cycles. Intermittent events refer to a series of transient events, typically characterized by arc faults and high-resistance faults occurring within relatively short durations (several seconds). [0003] Conventional detection methods are mainly based on phasor and Fourier results. Therefore, these methods actually target a steady-state sinusoidal signal. However, the results may ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/02G01R31/08G01R21/06
CPCH02H3/42G01R31/025G01R31/088G01R31/086H02H1/0015Y04S10/522H02H3/081G01R31/52H02H3/042H02H3/34H02H3/347Y04S10/52G01R31/08G01R31/50
Inventor 董辛舟崔涛薄志谦A·克利梅克A·尤什扎克
Owner AREVA T& D UK
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