Modified Electric Spring for Improved Power Quality in Power Grids

Clean, alternative renewable sources of energy like solar and wind energy will grow at an unprecedented rate. Challenges faced in integrating them into existing power grids have also been increasing, mainly due to their unpredictable and intermittent nature. It has been observed that various power system problems such as voltage sag/swell, harmonic distortions, power factor deterioration etc. are worsened as a result of the large scale integration of renewable sources into existing power systems. Their intermittent and unpredictable nature poses the serious threat of power and voltage instability in the grid. Flexible AC Transmission Systems (FACTS) like capacitors and inductors to complex, expensive computer controlled power electronic devices like SVCs, STATCOMs, DVRs, Unified Power Quality Conditioners (UPFCs) etc. offer compensation for power systems. Since most of these are implemented at transmission voltage levels with large capacity and complex compensators in transmission networks, new approaches on the distribution level for Demand Side Management (DSM) and stabilizing grids are required to deal with the uncertainty posed by increased use of distributed renewable energy sources. A modified control scheme for the Electric Spring (ES) based on synchronously rotating frame control is proposed which provides voltage regulation, real and reactive grid power compensation, power factor correction and reduced distortion. MATLAB simulation model and hardware results are given to validate the novelty of the circuit.