Abstract
This paper proposed an approximate calculation method to analyze the voltage in distribution system with distributed generation systems. The dependency of loads, distributed generation system, static var compensator (SVC) and energy storage system (ESS) on the voltage is represented by the exponential model. Applying the Taylor series approximation to the exponential model, we have found the linear relationship between the voltage and the current injection which is summation of currents flowing into the load, distributed generation system, SVC and ESS. In the electric transmission system, the imaginary part of the voltage drop between sending end and receiving end was ignored. It was found that these approximations enable us to make a linear equation of node voltage and obtain the approximate value of the receiving end voltage. It was shown that the error ratio of approximate value increases with the magnitude of line impedance. However, it was found that the application of the proposed method to the general distribution system enable us to analyze the voltage which is in error by up to 1%.
