Study On Microcomputer Distance Protective Device With Whole Line Sequent Quick Acting Function For 110kV Transmission Lines

As the expanding of the scale of the power system, the power user's demand for power quality is more and more high. It puts forward higher requirements for relay protection. Now, microcomputer protection device, which shows its unique advantage in high voltage power network, has already displaces traditional protection. China's 110kV lines assume the important task of the transmission and distribution, its operation mode and load always changes, therefore, research on a set of economical and practical protection device for 110kV line is of great significance.According to the characteristics of 110kV lines, this paper analyzes requirements of the device, puts forward the general function configuration, including three-segment phase-to-phase distance protection, three-segment ground distance protection, four-segment zero-sequence directional current protection, whole-line sequent quick acting protection, once 3-phase reclosure application, swing blocking, TV breakage blocking and so on. The paper also analyzes the basic working principle, technical characteristics and setting rules of the main and reserve protection.Against basic structure of the distance protection device, this paper puts forward the working principle and implementation scheme of starting element, phase selection element, phase-to phase directional impedance element, grounding directional impedance element, swing blocking element, TV breakage blocking element and once 3-phase reclosure element.At present, the circuit breaker has to trip after delay time through step-2 of distance protection when short-circuit fault occurs at the end of transmission line. A whole-line sequent quick-acting protection based on non-communication is put forward. The paper also introduced its working principle and implementation scheme in the microcomputer protection device based on double circuit lines with double terminal sources, single circuit line with multi terminal sources and single circuit line with double terminal sources.Starting from the hardware and software, this paper described the design of this protection device. The hardware design takes the chip TMS320VC33 of TI Company as the control center. This DSP has the advantages of fast calculating speed and high precision. The performance of the device is greatly improved. Last, we carried on static simulating experiment using relay tester, the test result proved its accuracy and reliability of the device.