A direct and rigid algorithm approach based on Equivalent Current Injection (ECI) for large-scale distribution power flow analysis is proposed in this dissertation. This algorithm used two primary matrices: BI and ZV-BC. Two matrices, which are built from the topological characteristics of distribution networks, are used to achieve the power flow solutions. BI matrix is the bus injection to branch current matrix and the ZV-BC matrix describes the relationship between the bus voltage mismatches and the branch current. The building algorithm is easily programmable and can be accomplished by a simple search technique with the two proposed matrices. Four connected cases are considered in this dissertation. The proposed algorithm is robust and accurate. Test results demonstrate the potential and validity of the proposed algorithm in distribution applications. Secondly, this thesis also presents a fault analysis with hybrid compensation for unbalanced distribution systems is proposed. The method employs the unbalanced three-phase model to analyze faults. BI and ZV-BC matrices containing information of the topological characteristics of distribution networks were built along with the proposed hybrid compensation method for analysis. Appropriate boundary conditions can be obtained for a fault to solve various types of single or simultaneous faults. The time-consuming LU decompositions, the Jacobian matrix, or the Y admittance matrix, required in the traditional algorithms, are not needed in the new development. Test results show that the proposed method is efficient, easy to program, also with advantages of high speed, robustness, improved accuracy, and lower memory requirements. This thesis also presents a hybrid programming (HP) technique to solve the reconfiguration problem for loss reduction and service restoration in Smart Grid application.

The thesis use capacitors, Static Synchronous Compensator (STATCOM) and wind generator to get optimal voltage stability for twenty-four-hour dynamic load by compensating real/reactive power. In the thesis, Modified Orthogonal Particle Swarm Optimizer (MOPSO) is proposed to find the sitting and sizing of capacitors, STATCOM and wind generator, and integrate Equivalent Current Injection (ECI) algorithm to solve Optimal Power Flow (OPF) to achieve optimal voltage stability. The algorithm uses MOPSO to renew STATCOM and wind turbine sizing Gbest with multiple choices and Taguchi orthogonal array, which improves Particle Swarm Optimizer (PSO) without falling into the local optimal solution and searches optimal voltage stability of power system by load balancing equation and inequality constraints. Average Voltage Variation (AVV) and Average Voltage Drop Variation (AVDV) are proposed as objective function to calculate whole system voltage variations, and convergence test of MOPSO. The IEEE 33 Bus distribution system and Miaoli-Houlong distribution system were used for simulation to test the voltage control during peak and off-peak periods of Taipower. Compensation of real/reactive power was used to get optimal system voltage stability for each simulated case.

The ¡§Congestion Management¡¨ (CM) always has been an outstanding and major problem in power system operation. To solve this problem, experts compose solutions in a wide variety. This thesis, based on the equivalent current, applies the Equivalent Current Injection (ECI) concept and circuit parameters to derive the Power Flow Tracing Method (PFTM) . By means of this method we can get a Sensitive Matrix (SM), which is also called the Contribution Matrix (CM), to show the linear relationship between the input power and tidal current discharge of each generator set, with the linear relationship we can derive the mathematic model of treating the congestion problem discussed in this thesis. Combining the Predictor-Corrector Interior Point Algorithm (PCIPA), we can manipulate the change of each generator set in the prospective of solving the congestion problem resulting from the system contingency (SC). The thesis performed various simulations for the IEEE 30 Bus system. Regarding the power contingencies, the solutions of the power-congestion problems can be resulted from the following incidents: heavy load addition, transmission line tripped, generator malfunction as well as the multi-contingencies, etc., which can all be solved with solutions within reasonably restricted domains. We can thus verify the effectiveness of the method .

With the deregulation of power industry and the market competition, reliable power supply and secured system operation are major concerns of the independent system operator (ISO). Power system operation under deregulated environment is very complicated with various possibilities of decisions involved. A robust and fast network analysis tool is one of important functions of conventional EMS, and this function will be reserved for the on-line analysis to deal with varied behaviors of the new deregulated environment. Firstly, a multiple-frequency three-phase load flow model was developed in this dissertation. There are two new sub-models including the fundamental power flow (FPF) and harmonic frequency power flow (HPF) model. In FPF, models of electrical elements and injected power on buses were treated in the form of current injections in a transmission system. The standard Fourier analysis was used to deal with the harmonic loads to get injection currents. With harmonic currents as equivalent current sources, the HPF can be derived. Besides, the fast assumptive model and decoupled model of FPF and HPF, called AFPF, DFPF and DHPF, were also proposed to improve execution time of the load flow programs. Test results show that the proposed general-purpose methods are better performers than conventional power flow solutions and are very robust. Secondly, the novel method, Upstream Tracing Model (UTM) and Downstream Tracing Model (DTM), to trace the power flow in transmission systems based on the converged AC power flow solution was proposed. The method is formulated by using the transmission network structure, the equivalent current-injection and load-admittances from the engineering viewpoint. Four steps are used to trace the linear relationship between each line flow and generator injection power without any assumption and the counter flow can be traced out, then the power consumption on each load can be represented as generators¡¦ contribution. According to the result of tracing, the loss of each line can be allocated to each generator by using a fair line usage concept. This tracing algorithm can calculate each generator¡¦s contribution quickly and fairly, and can be integrated into the existent tariffs of charging for transmission losses and services.

With the deregulation of power industry and the market competition, low cost, reliable power supply, and secured system operations are major concerns of the advanced deregulation markets. Power system protection is important for service reliability and quality assurance. To reduce the outage duration and promptly restore power services, fault section estimate has to be done effectively and accurately with fault alarms. First, an operational strategy for secondary power system restoration using Modified Grey Relational Analysis (MGRA) is proposed. The Restoration Scheme (RS) can be divided into three steps involving fault section determination, recovering process, and voltage correction process. Three GRAs are incorporated to design the overall restoration scheme. The first GRA uses network switching status to identify the fault. The second GRA combines switching states and load levels for network recovery. The third GRA uses capacitor bank control to support bus voltages. For security operation of restoration scheme, an Equivalent Current Injection (ECI) based hybrid current-power Optimal Power Flow (OPF) model with Predictor-Corrector Interior Point Algorithm (PCIPA) is used to verify the proposed scheme by off-line analysis to confirm a secure overall network operation including load-power balance, power generation limits, voltage limits, and power flow limits. The proposed method can further decompose into two sub-problems. Computer simulations were conducted with an IEEE 30-bus power system to show the effectiveness of the proposed restoration scheme and the PCIPA technique is very accurate, robust, and efficient for the modified OPF solution.