New optical differential protection algorithm applied in bus protection

Abstract

In order to improve the speed and reliability of bus protection, people put forward the optical current transformer (OCT) replaced the traditional electric–magnetic current transformer. As OCT has no magnetic saturation, no band limits, and can accurately and quickly transform the full-waveform current signal in principle, the authors put forward a new optical differential protection algorithm which directly use the integral values of the operating current and the restraint current measured by OCT as the differential protection algorithm. The authors build 220 kV double bus protection model and simulate the actual fault current signal by Real Time Digital Simulator (RTDS). Then, the authors bring the fault current into the bus protection algorithm for verification, and analyse the simulation curves of restraint ratio. The simulation results prove the feasibility of the optical differential protection algorithm.

Keywords

• power transmission protection
• power transmission lines
• electric current measurement
• current transformers
• fault currents
• relay protection
• power transformer protection
• power system protection
• restraint current
• kV double bus protection model
• actual fault current signal
• bus protection algorithm
• new optical differential protection algorithm
• optical current transformer
• traditional electric–magnetic current transformer
• magnetic saturation
• full-waveform current signal
• operating current
• voltage 220.0 kV