风电与火电“打捆”外送系统频率调控策略研究

风电与火电“打捆”外送是我国西部风电开发的一个重要特征。以具有典型意义的“风火打捆”仿真分析系统为例,研究了风电与火电之间的相互影响。围绕调差系数、前馈系数和伺服机构时间常数3个重要参数,分析了风功率波动条件下火电机组的一次调频特性。针对风机群体性脱网故障,提出了一种紧急提升火电机组功率的系统频率控制策略,通过监测风机脱网量和火电机组旋转备用量,计算火电机组的紧急提升功率量,将机组CCS由正常AGC控制切换为紧急提升功率的控制,实现减小系统频率波动幅度、提高频率稳定性的效果。针对电网侧不同的故障形式,比较了不同类型风机的响应特性。对固速风机在电网短路故障下发生转速失稳被过速保护切除的机理进行了较为深入的分析。

The Study of the Frequency Adjustment Characteristics of Wind Power Uniting Thermal Power Outgoing System

Wind power uniting thermal power outgoing is an important characteristic of China's western wind power development. In this paper, taking a typical significance wind power uniting fire power simplified system as an example, the interaction between wind power and thermal power is analyzed profoundly. Taking into account speed droop, feed-forward coefficient and servomechanism constant, the primary frequency regulation of thermal power units is analyzed under wind power fluctuation. The power system frequency control strategy of thermal power dealt with mass wind turbine off-grid is proposed to enhance mechanical power emergently. By monitoring the amount of off-grid wind turbines and thermal power spinning reserve capacity, the mechanical power of thermal power units enhanced emergently is calculated. Thus the CCS of thermal units from normal AGC control is switched to emergency power control. The frequency fluctuations are reduced and the stability of the system frequency is improved. The response characteristics of different types of wind turbines are compared in consideration of interruption and short-circuit fault of export power grid. The theory of solid-speed wind turbine removed by over-speed protection because of its speed instability is analyzed deeply under short-circuit fault.