Reactive power dispatch using distributed generation

• Main Author: Abbott, Stephen
• Published: Queen's University Belfast 2013
• Subjects: 333.79
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602402

Migrating from a legacy network, designed for centralised power production and control, to a network topology which allows for the integration of central and distributed generation has many challenges, The evolution of the network has to overcome the problems associated with integration of distributed generation (DG), These problems include the management of the network's voltage, reactive and active power flows, fault current, power quality and voltage stability issues, In this thesis a solution to the voltage control issue using reactive power dispatched from distributed generation is explored, This study predominantly presents a novel coordinate control stratagem utilising a sensitivity control algorithm to dispatch reactive power from distributed generation, The control stratagem is demonstrated on a balanced version of the IEEE 13 bus feeder, where it is shown to not only have the capability to maintain network voltages within the statutory limits, but also to reduce the requirement for network reinforcement and allow for greater accommodation of further distributed generation, The physical differences of unbalanced networks, and thus the requirement for an enhanced unbalanced controller, are presented for the unbalanced IEEE 13 node test feeder and Scottish and Southern Energy's We stray network. It is noted that unbalanced networks need to establish reactive power support for individual phases to ensure that networks operate within unbalanced limits, This is particularly necessary when stochastic generation is accommodated on the network. Proposals are presented for the connection of dynamic var (DVAr) compensation to ensure that the voltage imbalances, which will occur due to the connection of the proposed DG on the Westray system, are within the network requirements, It is also shown that the need for DVAr support can be elevated if the closure of the open point is allowed and the control strategy is utilised, From this work it is envisaged that dispatching reactive power from distributed generation could form an integral part of future networks if they too are operated effectively, efficiently and within voltage limitations, To allow this to happen, a number of changes to how distribution networks are operated and how DG is connected and compensated are required, The research highlights the importance of real-time monitoring and control of reactive power to better utilise the existing transmission and distribution infrastructure, whilst ensuring security and quality of power supply, It is further emphasised that adequate reward schemes or mandates for reactive power need to be implemented if sufficient reactive power is to be procured for network voltage support.