Granular Load-side Frequency Control With Electric Spring Aggregators And Leader-follower Consensus

Abstract

To utilise load-side control for frequency regulation in transmission networks, the designed control schemes need to be granulated down to the subtransmission level as only aggregate loads are used on the transmission level. Moreover, due to a higher R/X ratio in subtransmission networks, the active power changes caused by frequency control will influence bus voltages. To achieve the required active power response and regulate bus voltages, a control scheme is proposed for subtransmission networks by adopting electric spring (ES) aggregators consisting of ESs and non-critical loads. To implement the dual goals, the ES voltage of each ES aggregator is decoupled into d and q components. A distributed leader-following consensus algorithm is adopted for ES aggregators to control its active power consumption by sharing information with neighbouring aggregators. The d component of the ES voltage is adjusted accordingly to provide the required active power cooperatively. To avoid the consequent voltage variation, decentralised proportional–integral (PI) control is adopted for ES aggregators to adjust the q component of the ES voltage accordingly. Simulation results show that ES aggregators manage to achieve the required coordinated active power response to regulate frequency and keep bus voltages within the acceptable region under the proposed control method. © The Institution of Engineering and Technology 2018.