并联电容器组谐波微机保护装置的研究与设计

Research and design of microcomputer-based harmonic protection equipment for shunt capacitor

随着非线性用电设备的大量增加,电网谐波问题日益严重。并联电容器由于其本身的阻抗呈容性,更容易受到谐波的影响。此外,现有电容器的保护没有考虑到谐波带来的影响,导致在谐波环境下,电容器保护无法有效对电容器的安全运行进行保护。分析了谐波对现有电容器组保护的影响,在现有电容器保护的基础上设计了电容器谐波保护的方法及其整定原则。基于OMAP-L138处理器设计了一种新的并联电容器组谐波微机保护装置,除电容器组常规保护之外,实现了对并联电容器组单次谐波保护以及总谐波畸变率保护。最后通过实验室的测试验证了装置的精度及保护动作误差满足实际的运行要求。

With the increasing usage of non-linear devices, harmonic problem has become more and more serious in power grid. The shunt capacitor is very susceptible to harmonics because of its capacitive resistance. But existing capacitor protectors don’t take into account the influence of harmonics, resulting that shunt capacitor cannot be effectively protected under the harmonic surroundings. This paper analyzes the harm of harmonics to capacitors, puts forward new harmonic protection methods and setting rules, and designs a microprocessor-based harmonic protection equipment based on OMAP-L138 processor which can realize single harmonic protection and total harmonic distortion rate protection besides common protections for shunt capacitor. Finally, the accuracy and error of the harmonic protection equipment is verified by laboratory test.