基于相电流工频变化量极性的微电网纵联保护方案

Pilot Protection Scheme for Microgrid Based on the Polarity of the Power Frequency Variation of Phase Current

微电网能够充分利用分布式清洁能源,是智能电网的重要组成部分。然而,复杂的故障特征以及相对薄弱的硬件条件使得微电网保护难以确定,限制了其推广。对此,定义了工频变化量极性的概念,并提出了一种基于相电流工频变化量极性的微电网纵联保护方案。该方案首先利用本地相电流的工频变化量极性确定本侧电流总极性,然后通过两侧电流总极性识别故障区段。基于PSCAD的仿真结果表明,所提方案在微电网并网运行与孤岛运行条件下均能正确识别各类故障。

Microgrid can make full use of distributed clean energy,and it is a vital part of smart grid.However,complex fault characteristics and relatively weak hardware conditions make it difficult to set microgrid protection,which limits its promotion.In this regard,this paper defines the concept of the polarity of the power frequency variation,and proposes a microgrid pilot protection scheme based on the polarity of the power frequency variation of phase current.The scheme first uses the polarity of the power frequency variation of the local phase current to determine the total polarity of the current on the current side,and then identifies the fault section through the total polarity of the current on both sides.Simulation results based on PSCAD show that the proposed scheme can correctly identify various faults under the conditions of microgrid grid-connected operation and island operation.