Model for Planning Transmission Investments in Wholesale Electricity Market Using Simulink

Adetona, S.O (2010)

A Thesis Submitted to the School of Postgraduate Studies, University of Lagos

Thesis

Electricity business is globally metamorphosing into Wholesale Electricity Market (WEM) where market participants (MPs) trade in electricity. This engenders competition among MPs thus, imposing a great burden on the transmission network which, in consequence, may be operated in the way not originally envisioned. In order to allow healthy competitions among MPs and, at the same time, ensure security, reliability and availability of the grid, especially in a developing economy, there is the need for continued injection of new transmission investments into an existing grid. Injecting a new transmission investment requires proper technical planning, which includes identifying devices to be invested on; locating an optimal place to inject a new investment, predicting an optimal time for the injection of new investment and periodic evaluation of electrical load growth rate. These planning activities require sound models to carry them out. In that regard, this research developed a Transmission Investment Planning Model (TIPM), which can be used to determine optimal times for injecting a new transmission investment and, at the same time, evaluate the electrical load growth rate of a given grid. The TIPM is developed using the concept of dynamics of electrical loads on Available Transfer Capability (ATC) of each of the transmission paths of a given grid connected network. In this work, mathematical expressions for realizing TIPM are deduced, and they show that the Transmission Investible Time (TIT) is a function of Total Transfer Capability (TTC), Existing Transmission Commitments (ETC), Transmission Reliability Margin (TRM), electrical load growth rate (elGr) of each of the transmission paths that form the grid and a delimiter. The TIPM is realized in matlab simulink environment using deducible expressions. The model is tested in the matlab simulink environment using IEEE 14 bus test bed. One of the input signals to the heart of the TIPM is elGr of each of the transmission paths of the grid. In this work, therefore, the elGr model is developed using concepts based on the theory of growth function. It is built in matlab simulink environment, encapsulated and embedded in the TIPM to evaluate the rate at which electrical loads grow in a given WEM and used with other input information to predict new TIT. This sub-model is tested as a stand-alone model, validated with appropriate data, and found to be okay before it is embedded in the TIPM. This sub-model can be utilized by Market Operators (MOs) and MPs in the WEM process as a stand-alone model. In the course of building Transmission Investment Planning and electrical load growth rate models, it is realized that MPs need to capture the total power in MVA flowing through the transmission path of interest without necessarily having access to Transmission Service Provider (TSP) facilities. To that effect, the work develops a new algorithm for realizing wireless MVA meter. The new algorithm is developed using the Hall Effect Field principle. The algorithm is implemented in matlab simulink environment using embedded functions and math blocks; and results obtained from the simulink model, compared favourably with results obtained from a well known apparent power expression.

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