اثر مولد توزیع شده در محافظت از سیستم های قدرت Impact of Distributed Generation on Protection of Power System

I. Introduction The performance of distribution system is affected by distributed generation in various ways. As DG is related to renewable energy for lowering the environmental impact of power generation indicate a large scope for DG in future. DG improves voltage Profile but interfere with voltage regulation [1],[2]. The losses in a circuit can be minimized if DG is connected near to the load. The existing system did not deal with generation at distribution substation on radial feeder so such system where not designed to handle such power would be sent back to the source. Hence, accountable effect on the operation of existing protection may occur both false tripping and non-operations of protective devices are possible [3]. Selecting DG such a like that system operation will give a correct working after connecting DG in a network. Inserting DG will have an effect on the short circuit level, Transient stability of system, voltage and power quality. This paper gives an idea about the impact of DG on short circuit and load flow behavior are taken as a main disturbing parameter for effective protection. DG provides an additional fault current in the system. Fault current value depends on the parameter such as size, type, and location of DG. These additional fault current affect the performance of the system protection. II. Distributed generation Distributed Generation [5] (DG) is one of the new technology that gives a focused for the last few years and day by day its use in distribution networks is increasing. It is presented in many forms such as solar (PV), wind (wind farms) with small scale ratings up to 10MW. It is referred to generate electricity and supplying this electricity to customers with their locations, it can also be interconnected to the utility grids. There are so many exemptions of a DG gives to the customer, this privileges various types of advantages to install a DG rather than constructing new distribution lines. This DG can be used to provide electric supply to customers during peak load hours, it can satisfy a consumer demand apart from the grid, thus it can also support to an intentional islanding. One of the major problems that have to be considered to achieve a safe and effectively use of DG is its interconnection to the utility grid. III. Types of Distributed Generation DG can be classified into two major parts such as inverter based DG and rotating machine DG. After the generation process inverters are usually used in DG systems, as the generated voltage may be in DC form or AC. It has to be converted first to DC then back to AC so it is required to be changed to the nominal voltage and frequency with the nominal parameters through the rectifier.