脉冲负载作用下衡量电压畸变率的方法研究

独立小容量电力系统的电能质量与负载的功率特性密切相关。在柴油发电机组带脉冲负载孤岛运行的系统中,柴油发电机组的输出电压发生畸变,当负载作用强烈时,电压频率波动较大,难以确定其基波频率并有效分离出各次谐波含量,此时传统的电压总谐波畸变率(THDv)已不能应用。文中提出一种在脉冲负载作用下衡量交流电压畸变程度的方法, 即电压畸变率(DRV)。通过对柴油发电机组带脉冲负载运行的试验系统进行测试,对比分析了系统不同运行模式下的THDv与DRV,验证了所提方法的优越性和合理性。在此基础上,得到脉冲负载工作模式及发电机组输出功率的变化对交流侧DRV的影响规律。

A Study on the Method Measuring the Distortion Rate of Voltage under the Action of Pulse Load

The power quality of the independent low-power system is closely related to the load characteristics. In the system that the diesel generator set operates alone with pulse load, the output voltage of the diesel generator set is distorted. When the load changes suddenly, the voltage frequency fluctuates greatly, thus it is difficult to obtain the fundamental frequency and extract each harmonic effectively. In this case, it is useless to measure the distortion rate of voltage using the total harmonic distortion (THDv). Hence, a method measuring the distortion rate of voltage under the action of the pulse load, namely distortion rate of voltage (DRV) is presented. By testing the experiment system of the diesel generator set working with the pulse load, and comparing THDv with DRV in different operational modes, the method proposed in this paper is verified to be reasonable. At this base, the influence law of pulse load working mode and the generator output power to the DRV is obtained.