Real Time-Based under Frequency Control and Energy Management of Microgrids

Abstract

In this paper, an efficient under frequency control and the energy management of a distributed energy resources (DERs)-based microgrid is presented. The microgrid is composed of a photovoltaic (PV), double-fed induction generator (DFIG)-based wind and diesel generator with critical and non-critical loads. The system model and the control strategy are developed in a real time digital simulator (RTDS). The coordination and power management of the DERs in both grid-connected and islanded operation modes are implemented. During power imbalances and frequency fluctuations caused by fault or islanding, an advanced automatic load shedding control is implemented to regulate and maintain the microgrid frequency at its rated value. One distinct feature implemented for the load shedding operation is that highly unbalanced critical loads are connected to the microgrid. The diesel generator provides the required inertia in the islanded mode to maintain the microgrid rated frequency by operating in the isochronous mode. The International Council on Large Electric Systems (CIGRE) medium voltage (MV) test bench system is used to implement the DERs and their controller. The proposed control approach has potential applications for the complete operation of microgrids by properly controlling the power, voltage and frequency in both grid-connected and island modes. The real time digital simulator results verify the effectiveness and superiority of the proposed control scheme in grid connected, island and fault conditions.

Emerging Technologies in Power Systems

“…The operation and planning problems considering RESs systems are another focus of this Special Issue [7][8][9]. The paper in [7], entitled "Generation expansion planning in the presence of wind power plants using a genetic algorithm model", is introduced to improve the construction planning of power plants and save the cost of building various types of power plants.…”

“…A micro grid is a power system combined with RESs and an energy storage system (ESS) in a small area. The paper in [9], entitled "Real time-based under frequency control and energy management of microgrids", presents an efficient frequency control and energy management of micro grid. It provides a control method of power, voltage, and frequency in both the connected mode and the island mode.…”

A Synergetic Sliding Mode Controller Applied to Direct Field-Oriented Control of Induction Generator-Based Variable Speed Dual-Rotor Wind Turbines

“…Due to their mechanical features and favorable electricals, induction generators are widely used in the industrial sector, pumps, the military, automotive applications, and wind power [1]. Consequently, many works have been developed to enhance the effectiveness of induction generators [2][3][4]. Various control techniques for induction generators have been proposed in [5].…”

Islanding Detection Methods for Microgrids: A Comprehensive Review

“…Microgrid islanding occurs when the main grid power is interrupted but, at the same time, the microgrid keeps on injecting power to the network, which can be intentional or unintentional [12,13]. Intentional islanding is a controllable operation mode required for the maintenance of the main utility, whereas unintentional islanding is an uncontrollable operation caused by regular faults such as line tripping, equipment failure, or other uncertainties in the power system [14][15][16] and may degrade the power quality, overload the system, damage equipment and cause safety hazards [17][18][19][20]. Therefore, detecting the islanding condition and effectively disconnecting the microgrid within a specified time interval from the distribution network is a necessity.…”