适用于长距离输电网络的通用电压崩溃指标

摘要

首先提出一个广义电压崩溃指标(Generalized Voltage Collapse Index, 缩写为GVCI),定义为含有大容抗的长距离辐射型输电系统(架空线或海底电缆)距离最大稳定极限负荷的当前负荷裕度.GVCI为瞬时值,可用于保护和控制装置的整定,通过相量测量单元(PMU)所提供的局部测量值实现控制和保护功能.用一个简单的两母线双回线系统对所提出的GVCI指标的有效性进行了测试,通过扩展GVCI,用解析方式分析有载调压变压器(OLTC)的运行对电压崩溃的影响;并将GVCI与分析电压崩溃时常用的L指标进行了比较,讨论GVCI在地理位置偏远的风力发电场的可能应用.%A generalized voltage collapse index(GVCI) is derived which represents the distance to voltage collapse in terms of loading margin to maximum loading for long radial transmission system (or overhead/submarine cables) having substantial capacitive impedance. GVCI is an instantaneous value used to initiate the relay for control and protection by employing a set of local measurement provided by Phasor Measurement Unit (PMU). The effectiveness of the proposed GVCI is tested on a simple two-bus double circuit line and the effects of On-Load Tap Changers (OLTC) operation on voltage collapse have been analyzed analytically by extending the GVCI formulation to incorporate settings of OLTC. The proposed GVCI is compared with L-index for voltage collapse conditions. Finally, a possible application of the proposed index on remotely located wind farms is discussed.