Study on distance protection based on wide area information

In order to avoid the impact of the power system oscillation, distance protections are equipped with swing blocking element. If fault processing program procedures can not work out within 150ms, the distance protection will be blocked, which reduces the performance of the distance protection. With the development of communication technology and digital substation technology, the protection based on wide area information becomes a possible. This paper proposes a kind of wide area back-up protection system independent of traditional distance protection in high voltage grid, it uses the system parameters on the other end of the wide area information to improve the sensitivity of distance element, and uses wide area information to identify the circuit of the swing center and input swing open criterion only on the circuit. On this basis, a resetting scheme of back-up protection system action time, which is based on longitudinal protection discriminant result and takes the fault circuit as the center is put forward, the difficulty of rapid fault removal in the minimum range under the condition of the breaker refusal is solved. The backup protection system takes full advantage of the wide area information, and has advantages in areas of the sensitivity enhancement of distance components, improvement of traditional swing blocking strategy, and backup protection action speed. The distance protection coordinates with the existing power grid distance protection, the configuration and setting of the existing distance protection needn't change, the aim is to improve the performance of the back-up protection.