Turn-to-turn fault monitoring and protection identification method for dry-type air-core series reactor

Abstract

The invention discloses a turn-to-turn fault monitoring and protection identification method for a dry-type air-core series reactor of a parallel capacitor bank, and relates to the field of electricalequipment fault protection of a power system. At present, the understanding of triggering and exciting complex electromagnetic field energy conversion in the development process of the turn-to-turn short circuit fault of the capacitor bank parallel series reactor is lacked, and the turn-to-turn short circuit fault is not concerned to occur along with a secondary grounding fault. According to themethod, through acquiring bus PT voltage, acquiring CT three-phase current (Ia, Ib and Ic) of an angular inner sleeve of the angular wiring transformer or CT current I'a, I'b and I'c of a capacitor branch, HR (Iab), HR (Ibc) and HR (Ica) values or HR (I'a), HR (I'b) and HR (I'c) values are calculated in real time and mutual relations are identified. Fault identification and protection are realizedafter consistency identification of dominant frequency and reactance rate of harmonic current and bus grounding auxiliary signal identification, accurate identification and fault phase determinationcan be performed at the initial stage of turn-to-turn fault of equipment, and alarm and power supply cut-off can be performed in time.

Description

technical field [0001] The invention relates to the field of fault protection of electrical equipment in power systems, in particular to a method for monitoring and protection identification of inter-turn faults of dry-type air-core series reactors. Background technique [0002] In the parallel compensation capacitor bank (hereinafter referred to as parallel capacitance), in order to limit the inrush current and prevent harmonic amplification or resonance, a current-limiting reactor (hereinafter referred to as series reactance) is usually connected in series. Large-capacity outdoor parallel capacitors mostly use dry-type air-core series reactors (hereinafter referred to as air-core series reactors) for current limiting, and their typical faults mainly include: short-circuit between strands, short-circuit between turns, and flashover discharge on the surface of the envelope. [0003] Industry statistics show that inter-turn short circuit is the main fault type. This kind of ...

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Problems solved by technology

At the same time, since the total number of turns of the air-core series reactance is much smaller than that of the air-core parallel reactance, the short-circuit circulation current in the turns is also much smaller than that of the parallel-resistance short-circuit circulation, which determines that the development and expansion speed of the air-core series reactance inter-turn short circuit is relatively slow.

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