The authors would like to sincerely thank T. Aghdam et al. for their thoughtful discussion on our paper. They raise a valid, important and excellent point where the backup scheme of dual setting relays will not be fully coordinated properly. As such, one will experience, as stated by the discussers, for a fault at F1, R5 forward operation operating before R3 reverse operation. As suggested by the discussers, a possible solution would be to add (2) and this would yield both dual setting and conventional relay results the same and thus no improvement in operating times can be achieved by utilizing dual setting relays. The issue of possible loss of selecitivity but for definite time relays was reported in [1] and to resolve this issue, a communication link was used to block the operation of upstream relays [1] . This same approach can be applied to the dual settings relays and thus, another solution to resolve the dual setting selectivity problem would be to utilize a low bandwidth communication between relays which can then realize the full advantages of dual setting relays. The reported results in the paper can be achieved with proper protection coordination by amending dual setting relays with a low bandwidth communication that is utilized such that R1, once it detects an increase in current, would send a signal to block the unwanted operation of forward operating relays that are affected by that fault (for example, for a fault at F1, R1 forward operation sends a signal to block R5 forward operation and R5 forward operation sends a signal to block the forward operation of R4). This would apply to all relays in the system. Once again, we thank the reviewers for their careful review of the paper.

Closure to “Optimal Protection Coordination for Meshed Distribution Systems With DG Using Dual Setting Directional Over-Current Relays”

Frequency instability is a major problem in the Micro Hydro Power Plant (MHPP). To maintain frequency stability in Micro Hydro Power Plants (MHPP) using the governor system or Flow Control Valve (FCV). FCV as a regulator of the incoming water debit by opening the angle of the gate on the penstock using a servo motor as an actuator. By combining two methods of Fuzzy Logic Controller (FLC) and PI to provide an increase in system response. FCV has a disadvantage that is slow to respond if there is a sudden change in load. Therefore, it is integrated with Electronic Load Controller (ELC) which is considered better in terms of frequency response. However, this system generates harmonics that exceed the standard limits of IEEE 519-1992. The ELC circuit uses a three phase rectifier circuit. The ELC circuit flows the current on the load bus to the load ballast. ELC circuits require control techniques to determine the amount of current that is flowed to the ballast load. Using a PID controller combined with Adaptive Neuro Fuzzy Inference System (ANFIS). The combination of the two controllers to increase the response. So this study discusses how to integrate both FCV and ELC systems on MHPP so that it is more efficient than both FCV and ELC systems.

Optimasi koordinasi relay proteksi menggunakan dual simplex method

Reles tem a funcao de identificar os defeitos, localiza-los de maneira precisa e alertar a operacao do sistema para acionar a abertura de disjuntores, de modo a isolar o defeito, garantido seletividade. Reles de sobrecorrente podem ser utilizados como protecao principal ou protecao de retaguarda, em diversos tipos de sistema de potencia. Entretanto, um dos problemas decorrentes da utilizacao desses reles diz respeito a sua coordenacao, que visa obter a configuracao otima de atuacao, a fim de que o menor numero de consumidores fique sem o fornecimento de energia eletrica no caso de sua atuacao. Nesse contexto, sao aplicadas tecnicas de otimizacao atraves de algoritmos heuristicos. A metodologia utilizada neste trabalho para otimizar o tempo de coordenacao dos reles e a heuristica dos Lobos Cinzentos. Para o caso testado, a metodologia proposta obteve sucesso ao realizar a coordenacao dos reles na programacao nao linear, mantendo a seletividade do sistema de protecao, respeitando os ajustes e as restricoes impostas ao problema.

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Otimização do Tempo de Operação dos Relés de Sobrecorrente Através do Algoritmo dos Lobos Cinzentos

Overcurrent (OC) relay plays a major role in power distribution system. It protects electrical power systems against excessive current which are caused by faults like short circuits, ground faults, etc. It is necessary to clear the fault within a least possible time. The optimum time coordination of overcurrent relay in distribution network solved using Differential Evolution method and Dual Simplex method is presented in this paper. These methods are used to find the optimized values of time multiplier settings (TMS) of relays using linear programming problem (LPP). Differential evolution considers the present existing constraints to form the optimized values using mutation mechanism. Dual simplex gives the optimum solution without introducing any artificial variables. Differential Evolution and Dual simplex technique are presented in this paper for optimum time coordination of OC relays in a radial fed distribution system.

Jinka Rohit

Papers

Optimum coordination of overcurrent relays in distribution systems using differential evolution and dual simplex methods