Power-system protection

About: Power-system protection is a research topic. Over the lifetime, 6353 publications have been published within this topic receiving 117961 citations.

Reliability Analysis of Distribution System with Distributed Generation Considering Loss of Protection Coordination

Abstract: Distributed Generation (DG) is expected to improve the system reliability as its backup generation. However, DG contribution in fault current may cause the loss of the existing protection coordination, e.g. recloser-fuse coordination and breaker-breaker coordination. This problem can drastically deteriorate the system reliability, and it is more serious and complicated when there are several DG sources in the system. Hence, the above conflict in reliability aspect unavoidably needs a detailed investigation before the installation or enhancement of DG is done. The model of composite DG fault current is proposed to find the threshold that existing protection coordination is lost. Cases of protection miscoordination are described, together with their consequences. In addition, the issues of on-site DG and tie line are studied. Reliability indices are evaluated and compared in the distribution reliability test system RBTS Bus 2.

Coordination of generator protection with generator excitation control and generator capability

Abstract: This paper was written by a Working Group of the IEEE Power System Relay Committee to provide guidance to the industry to better coordinate generator protection with generator control. The paper discusses specific calculation methods that can be used to ensure that generator protection and excitation system control are fully coordinated. It also specifically addresses the coordination of relays with generator full load capability and machine steady state stability limits. Because of recent blackouts, NERC (North American Electric Reliability Council) is developing standards [1–3] for the coordination of generator protection and control. This paper provides practical guidance on providing this coordination.

Protective device coordination in an industrial power system with multiple sources

Abstract: Protective device coordination in an industrial power system with electric utility ties and multiple in-plant generators presents challenges which cannot be resolved by the use of conventional time-current curves. Relays in different locations will see greatly different currents during the same fault. This may be resolved by the use of the conventional per-unit time current curve. However, many computer aided time current curve programs do not support this technique. The coordination of time-overcurrent relays in this case can best be performed numerically using tables or spreadsheets. In addition spreadsheet techniques may be used for the setting of other relays, such as feeder protection relays. An example of the coordination of an industrial power system with multiple generators connected through a synchronizing bus, and which also has two utility ties is examined in order to illustrate these points.

An adaptive distance protection scheme for distribution system with distributed generation

Abstract: The value setting of the traditional distance protection has become very difficult for the distribution system with distributed generators (DGs) owing to the randomness of the DG output power. This paper proposes a new adaptive distance protection scheme to solve this problem. Firstly, on the basis of the connected point of DGs, the protected feeders are divided into different zones, with adaptive distance protection configured at the upstream side of DG. Then, based on a fault characteristic analysis of the distribution system with DG, the adaptive distance protection scheme for the distribution system with DG is studied to solve this problem. The results show that this scheme can automatically calculate the settings according to the operation mode and the output power of DG with no need for communication. Compared with the traditional adaptive protection scheme, the performance of this method is greatly improved. Simulation results on a 10 kV distribution system have verified the validity of the scheme proposed.

Artificial neural network approach to fault classification for double circuit transmission lines

Abstract: A novel application of neural network approach to protection of double circuit transmission line is demonstrated in this paper Different system faults on a protected transmission line should be detected and classified rapidly and correctly The proposed method uses current signals to learn the hidden relationship in the input patterns Using the proposed approach, fault detection, classification and faulted phase selection could be achieved within a quarter of cycle An improved performance is experienced once the neural network is trained sufficiently and suitably, thus performing correctly when faced with different system parameters and conditions Results of performance studies show that the proposed neural network-based module can improve the performance of conventional fault selection algorithms