基于SVG功率因数调节的光伏电站集中孤岛检测法

Centralized Islanding Detection Method for Photovoltaic Power Station Based on Power Factor Regulation with SVG

传统的主/被动式孤岛保护法应用于光伏电站孤岛检测时存在孤岛检测死区。文中首先分析孤岛前后电压和频率的变化情况,以及传统主动孤岛检测法应用于光伏电站时的失效机理,提出基于静止无功发生器(SVG)的集中防孤岛保护策略。根据光伏电站集中无功补偿的结构特点,在光伏电站低有功功率输出可能与本地负载功率匹配时,控制SVG输出的无功功率使得功率因数小幅波动,导致光伏电站系统输出的无功功率与本地负载消耗的无功功率不能匹配,以此来集中检测光伏电站的孤岛。理论分析和仿真验证结果证明该方法可以无死区检测孤岛。

The conventional passive and active islanding detection methods have large non-detection zones when employed to detect the islanding of the photovoltaic（PV）power station.The changing situation of voltage amplitude and frequency before and after islanding and failure mechanism of the typical conventional active islanding detection method is analyzed firstly.Then the centralized islanding detection method for PV power station is proposed.According to the structural characteristics of centralized reactive power compensation in the PV power station,when the low output active power of PV power station may match the consumed active power of local loads,regulating the power factor to fluctuate within a narrow range by controlling reactive power output by static var generator（SVG）,leading to the mismatching of reactive power between PV power station system and local loads,and islanding is detected accordingly.Theoretical analysis and simulation result has proven that the proposed method can accurately detect islanding of PV power station without none detection zone.