Voltage Control Techniques for Electrical Distribution Networks Including Distributed Generation

Abstract

Abstract:For the last three decades, a large scale integration of distributed generation (DG) is beginning to change the electrical distribution network from passive to active. Consequently, technical difficulties are created by significant impacts generated by DGs with voltage variation being the dominant effect. This paper presents a comprehensive review of voltage control techniques on electrical distribution networks connected with DG, recommendations are provided in terms of enhancing network voltage stability and maximising the DG utilisation.

Integrated Voltage and Power Flow Management Considering the Cost of Opera in Active Distribution Networks

“…A voltage excursion is defined as a voltage magnitude change that results in an out-of-specification anywhere on a network operating in its normal state [1] In comparison to transmission lines, the typical R/X ratio of a distribution network is relatively high; any significant power injection of DG units or heavy load conditions may result in voltage excursions on the distribution networks, especially in a weak distribution feeder with high impedance. Voltage excursions could occur under the following situations under normal operating condition: DG operating at maximum output during minimum load times; DG operating at low output, or disconnected from the network during peak load times; Currently, the most common measure to maintain a stable secondary voltage employed on distribution networks is the use of on-load tap changers (OLTCs) [1] The OLTC usually operates in conjunction with an automatic voltage regulator (AVR) relay and line drop compensator (LDC) as shown in Fig.…”

“…Voltage excursions could occur under the following situations under normal operating condition: DG operating at maximum output during minimum load times; DG operating at low output, or disconnected from the network during peak load times; Currently, the most common measure to maintain a stable secondary voltage employed on distribution networks is the use of on-load tap changers (OLTCs) [1] The OLTC usually operates in conjunction with an automatic voltage regulator (AVR) relay and line drop compensator (LDC) as shown in Fig. 1.…”

“…The stochastic nature of the power output of most forms of DG units result in a number of planning and operational uncertainties to the distribution network operators (DNOs) including voltage variations, bidirectional power flow, and system perturbations like harmonics or flickers; voltage variations and power flow uncertainties have been identified as the dominant effects [1] Intermittent power injections and unpredictable load may cause voltage excursions on weak distribution lines under extreme generation and loading conditions. Reverse power flows from DG units under low load and high generation scenarios may breach the thermal ratings on lines and transformers.…”

Model predictive control of voltage profiles in MV networks with distributed generation

“…(Kiprakis & Wallace, 2003;Vovos, Kiprakis, Wallace, & Harrison 2007;Viawan & Karlsson, 2008;Xu & Taylor, 2008;Hojo, Hatano, & Fuwa 2009;Gao & Redfern, 2010;AquinoLugo, Klump, & Overbye 2011;Turitsyn, Šulc, Backhaus, & Chertkov 2011;Yu, Czarkowski, & de Leon 2012;Liu, Aichhorn, Liu, & Li 2012). In coordinated solutions, a centralized controller maintains prescribed voltage profiles and reactive power flows, see e.g.…”

Voltage control in distribution networks using fast model predictive control

“…As a result, distribution networks are becoming active networks, having power flows in both directions. This ultimately means that new control applications are needed in these networks in order to ensure a proper and reliable operation of the distribution grid [4]. New control means that control strategies that have been used in the past to control the transmission grids, are not necessarily and exactly applicable for distribution grids.…”