Dynamics of inverter droop control and OLTC using power hardware in the loop (PHIL) - (ancillary services supply in low voltage grid)

Distributed Energy Resources (DER) sources installed closer to end users serve as local distributed generators, but they are regarded intermittent sources that pose a challenge to grid operators. Moreover, an increase in penetration of DER into the grid network has created problems related to power quality issues such as voltage sags and swells. The obligation of the grid operators to address power quality issues and energy demand has created an opportunity in the energy market due to the need for ancillary services. In resolving these power quality issues, the coupling DER-inverter becomes an effective tool in supplying ancillary services to the grid. This paper explores the dynamic functionality of a modelled droop-controlled inverter against the conventional OLTC transformers in a Low Voltage grid. The experiment is designed using the Power Hardware in the Loop (PHIL) test setup which combined a hardware DER-inverter, to a simulated low voltage AC distribution network. The test results show that inverter based DERs could enhance ancillary service provision at the distribution level by supporting the operation of the existing OLTC in realizing voltage control.