This paper proposes static and dynamic VAR planning based on the reactive power margin for enhanc... more This paper proposes static and dynamic VAR planning based on the reactive power margin for enhancing dynamic voltage stability of distribution networks with distributed wind generation. Firstly, the impact of high wind penetration on the static voltage stability of the system is analysed and then the effect of composite loads on system dynamics is presented through an accurate time-domain analysis. A new index, reactive power loadability (Q-loadability), is used to measure the vulnerability of the network to voltage collapse. Compensating devices are located using Q-loadability to increase the system voltage stability limit. Finally, a cost-effective combination of shunt capacitor bank and distribution static compensator (D-STATCOM) is determined through static and dynamic analyses to ensure voltage stability of the system after a sudden disturbance for different wind penetration levels. This study takes into account the induction motor dynamic characteristics which influence the transient voltage recovery phenomenon. The results show that the proposed approach can reduce the required sizes of compensating devices which, in turn, reduces costs. It also reduces power losses and improves the voltage regulation of the system.
ABSTRACT As existing distribution networks were designed to deliver unidirectional power to consu... more ABSTRACT As existing distribution networks were designed to deliver unidirectional power to consumers and require minimal control intervention, they result in largely passive infrastructures. The installation of distributed generation (DG) units with significant capacity in these passive networks can cause reverse power flows, which will result in some conflicts with the operation of the existing protection system. In this context, utilities around the world have started establishing requirements to ensure safe and reliable interconnection of generators in low- and medium-voltage networks. The technical grid code requirements and regulations vary considerably from country to country. However, any standard should address the critical need to make the DG marketable by providing uniform criteria and requirements relevant to the performance, operation, and safety. This paper presents a critical review of the requirements adopted by distribution companies in selected countries, such as the U.S., the U.K., Germany, and Australia, to facilitate the connection of DG. The main problems, such as voltage regulation, islanding operation, and dynamic interactions among DG and loads, are discussed to identify a few points where attention is still needed to improve the reliability of distribution systems.
This paper proposes static and dynamic VAR planning based on the reactive power margin for enhanc... more This paper proposes static and dynamic VAR planning based on the reactive power margin for enhancing dynamic voltage stability of distribution networks with distributed wind generation. Firstly, the impact of high wind penetration on the static voltage stability of the system is analysed and then the effect of composite loads on system dynamics is presented through an accurate time-domain analysis. A new index, reactive power loadability (Q-loadability), is used to measure the vulnerability of the network to voltage collapse. Compensating devices are located using Q-loadability to increase the system voltage stability limit. Finally, a cost-effective combination of shunt capacitor bank and distribution static compensator (D-STATCOM) is determined through static and dynamic analyses to ensure voltage stability of the system after a sudden disturbance for different wind penetration levels. This study takes into account the induction motor dynamic characteristics which influence the transient voltage recovery phenomenon. The results show that the proposed approach can reduce the required sizes of compensating devices which, in turn, reduces costs. It also reduces power losses and improves the voltage regulation of the system.
ABSTRACT As existing distribution networks were designed to deliver unidirectional power to consu... more ABSTRACT As existing distribution networks were designed to deliver unidirectional power to consumers and require minimal control intervention, they result in largely passive infrastructures. The installation of distributed generation (DG) units with significant capacity in these passive networks can cause reverse power flows, which will result in some conflicts with the operation of the existing protection system. In this context, utilities around the world have started establishing requirements to ensure safe and reliable interconnection of generators in low- and medium-voltage networks. The technical grid code requirements and regulations vary considerably from country to country. However, any standard should address the critical need to make the DG marketable by providing uniform criteria and requirements relevant to the performance, operation, and safety. This paper presents a critical review of the requirements adopted by distribution companies in selected countries, such as the U.S., the U.K., Germany, and Australia, to facilitate the connection of DG. The main problems, such as voltage regulation, islanding operation, and dynamic interactions among DG and loads, are discussed to identify a few points where attention is still needed to improve the reliability of distribution systems.
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Papers by Naruttam K Roy