Research And Manufacture Of New Transmission Line And Capacitor Protection Devices Integrated With Measurement And Control

This paper analyzes the evolvement and actuality of middle-low-voltage transmission line protection and capacitor protection. Combining with the development direction of integration and local-setting for middle-low-voltage protection devices, a new kind of protection device integrated with measurement, control and communication is researched and manufactured, which can install in high-voltage switch cabinet. The device has the characteristic of general-purpose, high reliability, anti-jamming ability. Then it is applied to transmission line and capacitor protection.According to design principle and function requirement of the protection device, this paper presents the layered hardware structure, which consists of the DSP-based protection module and ARM-based control module. On this hardware platform, the software is organized by programming modules to simplify software design and improve expansibility. All kinds of protection principle are realized by the format of protection logical function. Change between high and low sampling frequency and time-sharing protection management are used to satisfy the requirement of protection, measurement and control simultaneously.The paper presents the protection scheme of transmission line and capacitor based on the analysis of their fault and abnormal running state. Then it disserts the relevant protection principle and arithmetic.This paper analyzes and validates the characteristic of phase-to-phase differential current using the experiment dates. According to this characteristic, it presents an adaptive protection for middle-low-voltage transmission line based on phase-to-phase differential current and phase-to-phase voltage. This protection has the trait of adapting to the type of phase fault and the operating conditions of power system. Then, it analyses the performance of this adaptive instantaneous trip protection, and compares with the conventional current instantaneous trip protection, distance protection and voltage instantaneous trip with current blocking. And the superiority of the adaptive instantaneous trip protection is elucidated.According to the schemes of hardware, software and protection, a transmission line protection device is manufactured. The performance and function of the device are saw about through the static simulation and dynamic simulation experiments. The paper introduces the scheme and content of the experiments. And the results of the experiments are analyzed.