Single-phase earth fault analysis method for IIDG high-permeability small-resistance grounding system

Abstract

The invention discloses an IIDG high-permeability small-resistance grounding system single-phase grounding fault analysis method and belongs to the field of power system relay protection. The method comprises the following steps of determining an IIDG equivalent model according to an IIDG (Inverter-Interference Disturbed Generators) grid-connected control strategy and low-voltage ride-through technical requirement, and establishing an IIDG equivalent model according to the IIDG equivalent model; determining a grid-connected mode by integrating operation safety and protection principles, establishing an equivalent zero-sequence network of the multi-IIDG grid-connected system, and selecting a proper IIDG grid-connected grounding resistance value by combining personal safety and protection requirements; analyzing zero-sequence current amplitude and phase characteristics of the IIDG high-permeability small-resistance grounding power distribution network during single-phase grounding fault,and discussing high-resistance grounding fault characteristics.

Description

technical field [0001] The invention belongs to the field of relay protection of power systems, and in particular relates to a single-phase grounding fault analysis method of a small resistance grounding system with high IIDG penetration. Background technique [0002] Due to the low non-fault phase overvoltage of the single-phase ground fault, the small resistance grounding system can overcome the ferromagnetic resonance of the non-effective grounding system, the series resonance overvoltage of the arc suppression coil, and quickly cut off the ground fault. Dense large-capacity load cities such as Guangzhou, Shanghai and other cities are more and more widely used. However, when a single-phase ground fault occurs in a small-resistance grounding system, the magnitude of the short-circuit current is large, and operation with a fault is not allowed. The fault needs to be removed quickly to ensure power supply reliability and personal safety. Today's power operation calls for en...

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Problems solved by technology

Today's power operation calls for environmentally friendly and economical new energy power generation. The high penetration of DG in the small resistance grounding system will also be the future development direction. Some scholars at home and abroad have analyzed the structure of the general small resistance grounding system and single-phase ground fault characteristics, but did not consider too much the access of DG and the high penetration of IIDG, the impact of the change of system structure on the short-circuit current of single-phase ground fault and the series of problems brought about by relay protection are urgent Need to analyze and solve

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