This chapter focuses on voltage stability of microgrids. Some control schemes to maintain voltages of all the buses of a microgrid at acceptable levels in normal conditions and after being subjected to disturbances will be presented. Voltage stability enhancement and reactive power sharing in inverter-based microgrids are discussed, including droop-control techniques.

Chapter Contents:

• 10.1 Introduction
• 10.1.1 Concept of voltage stability
• 10.1.2 Voltage stability issues of microgrid
• 10.1.3 Microgrid voltage stability assessment
• 10.1.3.1 Static voltage stability analysis
• 10.1.3.2 P–V and Q–V curves
• 10.1.3.3 V–Q sensitivity analysis
• 10.1.3.4 Dynamic analysis
• 10.1.3.5 Proximity to voltage instability
• 10.2 Small-signal model of a microgrid for voltage stability analysis
• 10.3 Voltage stability enhancement
• 10.4 Case studies
• 10.4.1 Case study 1
• 10.4.1.1 Small signal model of the inverter—case study 1
• 10.4.1.2 Small signal model of the power network—case study 1
• 10.4.1.3 Small signal model of the load—case study 1
• 10.4.1.4 Small signal model of the whole system—case study 1
• 10.4.1.5 Stability analysis—case study 1
• 10.4.2 Case study 2
• 10.4.2.1 The synchronous generator model—case study 2
• 10.4.2.2 The inverter model–case study 2
• 10.4.2.3 Model of the inverter control system—case study 2
• 10.4.2.4 Network model—case study 2
• 10.4.2.5 Model of the whole system—case study 2
• 10.4.2.6 Voltage stability analysis—case study 2
• 10.4.3 Case study 3
• 10.4.3.1 Models of the induction generator and the whole system—case study 3
• 10.4.3.2 Stability analysis—case study 3
• 10.4.4 Case study 4
• 10.4.4.1 The context: current status and future perspective of microgrids in Oman
• 10.4.4.2 Conclusion and recommendations for case study 4
• 10.5 Concluding remarks
• References
• Further reading

Inspec keywords: distributed power generation; voltage control; power system stability; invertors; power generation control; reactive power control

Other keywords: reactive power sharing; buses; acceptable levels; normal conditions; inverter-based microgrids; voltage stability enhancement; droop-control techniques; control schemes

Subjects: Control of electric power systems; Power electronics, supply and supervisory circuits; Power system control; DC-AC power convertors (invertors); Distributed power generation; Power and energy control; Stability in control theory; Voltage control