Method and apparatus for detecting a fault section in ungrounded distribution power systems

Abstract

The present invention provides a fault section detection device for detecting fault section by comparison of phase difference, and magnitude of zero-phase current in non-grounded distribution system. The device includes the following parts: line terminal devices which are installed to each section of the lines in the non-grounded distribution system so as to measure inter-line short circuit voltages and the zero-phase currents to transmit the phase differences and magnitude of the zero-phase currents to a central controller after calculating them, and to execute the opening / closing command of a switch corresponding to instructions of the central controller; a circuit fault detection device for detecting whether the circuit happens fault and transferring the detection result to a central control device; and a central control device which requests the line terminal devices to transmit the phase difference and magnitude information and judges the fault section of relative lines after it receives the fault information from the circuit fault detection device, and closes a connection switch, separates the fault section from the system, and switches the normal section to a special line to continue to supply power to load. The invention can easily judge the fault section and supply power to the load under the condition of no power interruption.

Description

Technical field [0001] The invention relates to a method and device for detecting a fault section located by comparing the phase difference and magnitude of zero-phase current in an ungrounded power distribution system. The present invention causes a circuit failure when a single-phase ground fault occurs in the ungrounded power distribution system. The whole system is composed of the detection device, the terminal that can measure the line voltage and the zero-phase current, and the central device. After comparing the phase difference and the magnitude of the zero-phase current and the line voltage measured by each terminal of the line, the fault area is located. Section, and the method and device for isolating the faulty section from the system without power failure. Background technique [0002] Generally speaking, ungrounded power distribution systems are suitable for systems with short lines and low voltages. The capacitance to ground of this line is small, so the charging c...

AI Technical Summary

Problems solved by technology

Although the protection method used in Japan can judge the fault circuit and locate the fault section through the forward delivery method, however, due to the forward delivery method, it is inevitable to stop the power supply to the load during the process of locating the fault section. The increased number of opening and closing times also increases the possibility of circuit breaker switching failure

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