Transfer capability computations in deregulated power systems

With the recent trend towards deregulating power systems around the world, transfer capability computation emerges as the key issue to a smoothly running power market with multiple transactions. Total Transfer Capability (TTC) is the basic measure for evaluating available transfer capability (ATC). The paper presents the calculation of TTC through an optimal power flow approach. The objective function is to maximize the sum of the sending end-end generation and receiving-end load of specified buses. The constraints are ac power flow equations and system operation limits. The sequential quadratic programming (SQP) method is used for the optimization process. The IEEE 30 bus system is used for testing the proposed algorithm and the results compared favorably with that from the Continuation Power Flow (CPF) method.published_or_final_versio

Optimal Power Flow with Hybrid Distributed Generators and Unified Controller

Optimal power flow (OPF) study is conducted on a power system to achieve one of the following objectives: cost/loss minimization or available transfer capability (ATC) calculation in a deregulated environment. Distributed generation (DG) is a small source of electric power conversion from non-conventional energy sources and Hybrid DGs which often the most cost-effective and reliable way to produce power. The optimality of control variables and minimum value of objective functions in OPF study would definitely change when DGs are interconnected to the grid. The change would be respect to the location, quantity and combination of power injection by DGs. On the other hand, FACTS controllers are effective in utilizing the existing of transmission network which is very important especially in a deregulated system. Unified power flow controller (UPFC), a second generation FACTS controller, is well known for minimizing the cost of generation/losses with a good voltage profile as well as for ATC improvement. This paper conducts a detailed OPF study on a 9 bus system for the above mentioned three objectives to analyze the effect of DGs with and without UPFC. From the results, it is found that hybrid DGs along with UPFC yields better performance in many aspects

Transmission planning in a deregulated environment

The worldwide trend for the deregulation of the electricity generation and transmission industries has led to dramatic changes in system operation and planning procedures. The optimum approach to transmission-expansion planning in a deregulated environment is an open problem especially when the responsibilities of the organisations carrying out the planning work need to be addressed. To date there is a consensus that the system operator and network manager perform the expansion planning work in a centralised way. However, with an increasing input from the electricity market, the objectives, constraints and approaches toward transmission planning should be carefully designed to ensure system reliability as well as meeting the market requirements. A market-oriented approach for transmission planning in a deregulated environment is proposed. Case studies using the IEEE 14-bus system and the Australian national electricity market grid are performed. In addition, the proposed method is compared with a traditional planning method to further verify its effectiveness

Application of Cubic Spline Interpolation Technique in Power Systems: A Review

In this chapter, a comprehensive review is made on the application of cubic spline interpolation techniques in the field of power systems. Domains like available transfer capability (ATC), electric arc furnace modeling, static var. compensation, voltage stability margin, and market power determination in deregulated electricity market are taken as samples to illustrate the significance of cubic spline interpolation

Power market analysis tool for congestion management

The privatization and deregulation of electricity markets has increased competition and electricity may be produced and consumed in amounts that would cause the transmission system to operate beyond transfer limits---the system is congested. Hence, congestion management is a fundamental transmission management problem. In this thesis, a power market analysis tool is designed for congestion management. The tool creates an interface between PowerWorld (c), a professional software tool to compute power flows, and MATLAB RTM. The tool helps in analyzing power flow results, batch-processing of large case studies, and providing the user with options to manage congestions. A graphical user interface has been designed to help the user learn and interact with the tool.;Based on the generator and load bid data, the tool performs (N-1) security analysis. In case of congestion, the user can choose one of three congestion relief methods. Transmission Line Relief Sensitivity (sensitivities of line flows to load curtailment), Economic Load Management (a product of three indices that measure (i) the sensitivity of the line flow to load curtailment, (ii) the level of customer incentive to cut down consumption, and (iii) the customer\u27s acceptable range of curtailment), and VAR Support (installment of additional VAR devices). The congestion alleviation methods are explained and tested on a six bus test system and the IEEE 24 bus Reliability Test System

ATC Enhancement With FACTS Devices Considering Reactive Power Flows Using PTDF

In the present day world power system deregulation is at its full stretch. In this deregulated environment there is a clear need for adequate computation of ATC which is currently being given at most importance. The insertion of FACTS devices in electrical systems seems to be a promising strategy to enhance ATC. In this paper, the viability and technical merits of boosting ATC using TCSC are analyzed. The methods used for determining ATC are linear methods, which are based on MVA loading of the system considering system thermal limit constraints, neglecting bus voltages and static collapse. Power Transfer Distribution Factors, commonly referred to as PTDFs, express the percentage of a power transfer that flows on a transmission facility. They are used to determine the maximum ATC that may be available across the system without violating line thermal limits. The effect of reactive power flows in line loading is not considered in linear ATC which is a major limitation. This paper describes a fast algorithm to incorporate this effect. In this paper the line post transfer complex flow is estimated based on exact circle equation and then ATC is evaluated using active power distribution factors. The effectiveness of the proposed method is successfully demonstrated on IEEE 30-Bus system.DOI:http://dx.doi.org/10.11591/ijece.v3i6.392