Digital current protection method for alternating-current looped serial power supply mode of subways

Abstract

The invention discloses a digital current protection method for an alternating-current looped serial power supply mode of subways, which is mainly implemented through that according to a situation that whether a main transformer station in the process of normal running is located on the left side of a circuit breaker, two kinds of fault judging section startup signals are respectively sent to left and right adjacent circuit breaker protection devices; after the protection starts, the received adjacent circuit breaker fault judging section startup signals are divided into two sets according to a situation that whether a signal source is located on the left side or right side of the protection device, if one signal in each set of signals is logically true, the set of signals is regarded to be logically true; if the two sets of signals on the two sides are all logically true, the digital current protection of the two sides is locked and judged as external faults; and otherwise, once one set of signals on the left side or right side is logically false, the digital current protection is judged as internal faults, and a quick motion outlet for digital current protection clears the faults. According to the characteristics and development trend of medium-voltage power supply systems for subways, the method is economic and reliable and easy to maintain, and can adapt to the large looped network power supply mode of subways.

Description

Technical field [0001] The invention belongs to the field of microcomputer protection of power systems, and is suitable for microcomputer protection of 10kV or 35kV medium voltage ring networks of subways and urban light rails, and other fields with similar network structures. Background technique [0002] The layout of the subway medium voltage power supply system can be simply divided into three types: large-loop string power supply, small-loop string power supply, and distributed power supply. [0003] The decentralized power supply method does not have a main substation. The subway power supply is provided by the 110kV substations that have been built along the subway line in the city. The voltage level of the medium voltage power supply system is 10kV. The 10kV subway system adopts a dual-ring network dual-terminal power supply mode, each section of the ring network has 3 to 5 station substations, and there is a support power supply mode between the two power sources. The cit...

AI Technical Summary

Problems solved by technology

There are usually hundreds of protection devices for a subway line, and dozens of devices in a power supply ring string. Manually switching the setting method reduces the convenience of operation;

[0015] 3) For bus faults in station substations, due to the insufficient selectivity of overcurrent protection in the current protection scheme, the fault area cannot be determined, so the area isolation function for bus faults cannot be realized

[0016] The power supply network structure of the power distribution system has certain similarities with the subway medium-voltage ring network system. Although the Chinese patent application CN201010565045.5 "Method Based on Power Distribution Network Topology Protection" can solve some problems of the subway ring network protection, but the The method cannot determine that the fault area is located in the left protection area or the right protection area of ​​the circuit breaker, so the fault area isolation function required for subway operation cannot be realized, and this method needs to switch the fixed value group after the subway operation mode is switched, which cannot To achieve self-adaptation to the operation mode, the convenience of operation is insufficient, and it cannot meet the application requirements of the medium-voltage ring network power supply system of the subway

Images