Study On Algorithm And Communication Of Adaptive Protection System Of Power Supply And Distribution Line

Protective relays are necessary part for power system's safe operating. Traditional protective relays have no or worse communication ability. Their settings are gotten off-line and are invariable in operating. So they can not get the optimal protecting effect and can not satisfy selectivity, speediness and sensitivity of power system sometimes. Adaptive protection can get its settings on-line and the optimal operating state. Adaptive protection device uses local information only and can only adapt to changes of system impedance of less area of power system. Via communication network, adaptive protection system uses information of the system, realizing strategy of adaptive protection function and adatpvie protection algorithm. It can adapt to various changes of system impedance of power system and get the optimal protecting effect. Adaptive protection algorithm, wavelet amplitude algorithm, key technologies of DeviceNet, transmission delay of DeviceNet and Ethernet communication are studied and a new adaptive protection system of power supply and distribution line is designed in this dissertation. Its application can improve the selectivity and sensitivity of power supply and distribution line protection.On the base of investigating the research status of adptive protection system, an adaptive protection system of power supply and distribution line of 35kV or under 35kV is constructed based on DeviceNet fieldbus, industrial Ethernet and the offered system's overall structure. It is composed of production process level, bay level, substation level and central control center level. To solve the problem of adaptive protection function's realization, adaptive setting algorithm, realizing strategy of adaptive protection function of the system and adatpvie protection algorithm of the device are presented. The adaptive setting algorithm and realizing strategy of adaptive protection function use local information of adaptive protection device, information of substation, status messages and topology connection relations coming from SCADA system offered by centralized control center to adapt to changes of topology structure, system impedance and fault type by amending the settings on line. The adatpvie protection algorithm of the device is adaptive three-step current protection...