Method for limiting line short-circuit currents by using twin-core controllable phase shifter

Abstract

The invention discloses a method for limiting line short-circuit currents by using a phase shifter. When the system is in normal operation, the number of turns of auxiliary side windings of a shunt transformer ET of the twin-core controllable phase shifter is adjusted by an electronic power switch so that the auxiliary side windings of the shunt transformer ET can be in different link group states. When symmetrical short trouble or asymmetrical short trouble occurs to a circuit or an adjacent circuit where the twin-core controllable phase shifter is placed, a relay protection device sends a separating brake instruction to a high-voltage circuit-breaker, meanwhile, the relay protection device sends a control instruction to the twin-core controllable phase shifter, the electronic power switch rapidly opens circuits for the auxiliary side windings of the shunt transformer ET and a series transformer BT of the twin-core controllable phase shifter, and before a movable contact and a fixed contact of the high-voltage circuit-breaker are separated, the circuits of the auxiliary side windings of the shunt transformer ET and the series transformer BT of the twin-core controllable phase shifter have already been opened. In an intrinsic separating brake time of the high-voltage circuit-breaker, when the high-voltage circuit-breaker starts arcing in an arc extinguishing chamber, the line short-circuit currents has already been limited in a quite low level, and therefore the reigniting or restriking probability of the high-voltage circuit-breaker is effectively lowered.

Description

technical field [0001] The invention relates to the technical field of limiting the short-circuit current of a line in a power system, in particular to a method for limiting the short-circuit current of a line by using a double-core controllable phase shifter. Background technique [0002] Due to the increasing demand for electric energy in social life and economic development, the total power supply capacity of the power system is increasing day by day, and the density of the power grid is increasing day by day. These two basic reasons have caused the level of short-circuit current in the system to continue to rise. [0003] In this context, when the power system encounters a short-circuit fault due to component damage, weather conditions deterioration, or illegal operation, the short-circuit current level will exceed the breaking capacity of the circuit breaker on the line, causing the fault to fail to be removed normally, causing more serious damage. System failure, even ...

AI Technical Summary

Problems solved by technology

When the short-circuit current exceeds the breaking capacity of the existing circuit breaker, there are two ways to deal with it: one is to replace the large-capacity circuit breaker, but it involves issues such as equipment manufacturing capacity, foundation, dynamic and thermal stability of auxiliary parts, and communication interference. , needs to be considered comprehensively, too large circuit breaker equipment breaking capacity is uneconomical; the second is to conduct comprehensive research on the combination of power grid planning and design, system operation mode, electrical equipment manufacturing and installation, specifically 1. Segmented operation of low-voltage power grid; 2. Coordinated development of voltage levels; 3. Multiple busbars run in parallel or busbars in sections; 4. Separate grid; 5. Adopt DC power transmission technology (back-to-back BTB); 6. Adopt high-impedance equipment; 7. Current limiting The use of reactors; 8. Transformers are grounded through small reactances; 9. Microcomputer protection and integrated automation devices are used; 10. Short-circuit current limiters, etc.

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