Influence Of Power Relay Protection For Distribution Generation And Solution Research

As a kind of efficient, economical and reliable energy, distributed generation (DG) have been attracting intensive attention at home and abroad recently. The fast development of DG has brought new challenges and influences to traditional Power system. Most distribution networks especially rural systems are operated in a radial configuration, and the protection of distribution systems are based on this configuration. Installation of DG will not alter the topology of the system, but the power will be able to flow in multiple directions. This fundamental change in operating principle can restrict the operation of the protection system causing false tripping of feeders, blinding of protection and increased or decreased fault levels.DG can be divided into the inverter-based distributed power and the traditional distributed power. For the conditions of three-phase short circuit, two-phase short circuit and single phase short-circuit, this paper studied and compared the influence of protection for inverter-based distributed power and traditional distributed power, come the conclusion that under the same capacity, the impact of the inverter-based distributed power is less than the traditional distributed power. In addition to the factor of the type of distributed power, this thesis analyzes the other factors includes the capacity for distributed power, the installation location and the fault location.Wind power generation is the most widely used as a distributed power. This paper builds a model of doubly fed wind turbine in PSCAD/EMTDC simulation software, focused on studying the control of rotor side and grid-side converter in the doubly fed wind turbine by changing the fault location and the access points of the distributed generation, through comparison of the dates, this paper verifies the theoretical analysis.For the impacts of the distribution that are due to the distributed generation, this paper proposes the new current protection. The protection is based on the improvement of traditional three-zone current protection, so that it has quick action and flexible configuration.Moreover, it does not have to modify the Protection values frequently after DG connected to the system and verifies it through simulations.