Enhancing the situational awareness of the active distribution network
Khan, Maman Ahmad
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Power distribution system operation has become increasingly complex with the large-scale integration of Distributed Energy Resources (DERs). This has led to a paradigm shift in the operation and planning of the power distribution network. Following the integration of DERs, situational awareness has become very important in distribution systems, including the primary and secondary distribution networks. The major aim of situational awareness is to provide operational visibility of the network, enabling the key information for a stable power distribution network. The foremost step for better situational awareness is integrating high-performance monitoring devices capable of monitoring the distribution network in real-time. Existing time synchronised measurement devices such as Phasor Measurement Units (PMUs) were primarily designed for transmission network monitoring. For economic reasons, these are not viable for monitoring Medium Voltage (MV) and Low Voltage (LV) distribution networks with vast numbers of nodes. Therefore, the fi rst part of this thesis proposes a monitoring device integrating smart meters using the IEEE-1588 protocol for time synchronisation purposes. This addresses the need for improved monitoring and situational awareness in MV and LV distribution networks. Test results indicate the proposed technique is expected to reduce the overall cost of the distribution network monitoring implementation compared to the system based on high-cost Phasor Measurement Unit (PMUs). These results are possible with the help of utilising the already existing smart meter's sensors to collect measurements and synchronise them using the IEEE-1588 time synchronisation technique. The next part of the thesis focuses on proposing a uniform time synchronisation technique for different distribution network applications. These applications utilise a uniform homogenous time synchronisation technique with different time criticality. A test bench is established to analyse the IEEE 1588 protocol for different time stampings showing seamless and cost-effective deployment in the distribution network. The third part of the thesis proposes a robust Distribution System State Estimation (DSSE) considering the measurements available at the LV level of the network. Computational complexity is considered to be an important factor in state estimation performance at the MV and LV levels. Therefore, this thesis proposes a linear state estimation technique for low voltage networks that solves the challenge of iterative approaches that are generally sensitive to erroneous measurement and are not computationally efficient. The effectiveness of the proposed algorithm is evaluated using a novel modi ed IEEE 906 European low voltage network, and the outputs of the state estimation studies are compared with the already existing literature. The proposed algorithm provides a two-layer state estimation technique for a realistic, unbalanced MV/LV distribution network which solves the convergence problem in the radial LV network caused by high R/X ratios. The utilisation of the LV state estimation states as the MV level measurements increases the state estimation accuracy while also reducing the need to install high-cost MV meters for monitoring purposes.