Modeling of a Dstatcom with Ultra-capacitor Energy Storage for Power Distribution System Applications

Utility and customer-side disturbances result in bus voltage fluctuations, transients, and waveform distortions on the distribution system. Just as flexible AC transmission systems (FACTS) permit to improve the reliability and quality of transmission systems, these controllers can be used in the distribution level with comparable benefits for bringing solutions to a wide range of problems. In this sense, FACTS-based power electronic controllers for electric distribution systems, namely custom power (CP) devices, are able to enhance the reliability and quality of power provided to customers. This situation is especially significant when dispersed or distributed generation (DG) based on wind generation is connected in the area, so that stabilizing devices are strongly needed to maintain reliable and stable operation of the power system [1]. A DSTATCOM is a fast response, solid-state power controller that provides flexible voltage control at the point of connection (PCC) to the utility distribution feeder for power quality (PQ) improvements. It can continuously generate reactive power by varying the amplitude of the inverter voltage with respect to the line bus voltage so that a controlled current flows through the tie reactance between the DSTATCOM and the distribution network. This enables the DSTATCOM to mitigate voltage fluctuations such as sags, swells, transients and to provide voltage regulation, power factor correction and harmonics compensation. [2]. The addition of energy storage through an appropriate interface to the CP device leads to a more flexible integrated controller. The ability of the DSTATCOM−ESS for supplying effectively extra active power allows expanding its compensating actions, reducing transmission losses and enhancing the operation of the electric grid. Various types of advanced energy storage technologies can be incorporated into the DC bus of the DSTATCOM, namely superconducting magnetic energy storage (SMES), ultra-capacitor energy storage (UCES) and flywheel energy storage (FES), among others. However, ultra-capacitors have distinct potential advantages for energy storage which make them almost unbeatable in many applications [3]. Because they have no moving parts, and require neither cooling nor heating, and because they undergo no internal chemical changes as part of their function, they are very efficient and robust. Also, they require practically XIII ERIAC DÉCIMO TERCER ENCUENTRO REGIONAL IBEROAMERICANO DE CIGRÉ