This paper develops appropriate models of flexible ac transmission systems (FACTS) shunt-series controllers for multiobjective optimization and also presents a multiobjective optimization methodology to find the optimal location of FACTS shunt-series controllers. The objective functions are the total fuel cost, power losses, and system loadability with and without minimum cost of FACTS installation. The e-constraint approach is implemented for the multiobjective mathematical programming (MMP) formulation, including the FACTS shunt-series controllers (i.e., phase-shifting transformer (PST), hybrid flow controller (HFC), and unified power-flow controller (UPFC)). Simulation results are presented for the IEEE 14-bus system. The optimization method is numerically solved using Matlab and general algebraic modeling system (GAMS) software environments. The solution procedure uses nonlinear programming (NLP) and mixed-integer nonlinear programming (MINLP) to solve the optimal location and setting of FACTS incorporated in the optimal power-flow problem considering these objective functions and improving the power system operation. Furthermore, the results demonstrate that the HFC is outperformed by PST and UPFC from the analytical and technical point of views.

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Multiobjective Optimal Location of FACTS Shunt-Series Controllers for Power System Operation Planning

In this paper a practical model of phase shifter has been described. By using this model a symmetrical Y-bus matrix can be preserved in the load flow calculation. On this basis a simplified real power flow control algorithm by phase shifter is described. This model has also been used to solve the problems of overloads in contingency analysis and minimizing line losses in transmission systems.

Phase Shifter and Power Flow Control

A solid-state, pulse-width-modulated (PWM) phase shifter, based on gate-turn-off )GTO) thyristors or other valves with force commutation capabilities, is described. Besides serving the phase-shifter function, it offers regulated control over three independent quantities: the real power passing through it and the VAR (volt-ampere reactive) on both sides to which it is connected. The power transferred can be bidirectional, and the VArs can be leading or lagging. Digital simulations show that the PWM phase-shifter reported here is capable of regulated control of bidirectional real power flow and independent regulated control of positive or negative VArs on both sides of the phase shifter. >

A solid-state PWM phase-shifter

The present invention provides an arbitrage control system for two or more available power sources (106, 108) that enables the automatic or manual control of one or more multi-source systems (202) to take advantage of price differentials across commodities, locations and/or time. The present invention selects a power source for a device or delivery point (110) from two or more available power sources (106, 108) by analyzing market and operational data (406). A power source (106 or 108) for the device or delivery point (110) is then selected from the two or more available power sources (106, 108) based on a set of financial parameters (408). If the device or delivery point (110) is not already connected to the selected power source, one or more signals are sent (418) to switch the device or delivery point (110) to the selected power source. The arbitrage controller (102) includes a user interface (300), market interface (302), multi-source interface (304), database (306) and processor (308). The processor (308) is communicably coupled to the user interface (300), the market interface (302), the multi-source interface (304) and the database (306).

Arbitrage control system for two or more available power sources

This survey article deals with the complex topic of transmission capacity, starting from its definition through modeling and analysis. Methods for evaluating transmission capacity are also briefly described. The second part of the article is concerned with possible means of increasing the transmission capacity at the locations of most interest. The third part is concerned with possible economic incentives for enhancing transmission capacity in a changing electric power industry.

Transmission capacity in power networks

In the operation of an electric power distributing system involving various kinds of networks, a fundamental necessity is that each transforming and transmitting unit carry a reasonable share of the total load. In the case of a single system that has been developed in a coordinated manner the problem of load division has not in general been troublesome and has been solved by judicious selection of parallel circuits, use of reactors, proper system set-up, etc. The advent of inter-company connections has brought together systems of varying characteristics, changed the relation between the basic elements involved, and in some cases has made difficult the control of power flow over tie lines small in comparison to the systems which they unite. It is the purpose of this paper to discuss the case of load control where closed rings or parallel path circuits are involved. After briefly reviewing the principles of voltage phase angle and power flow, a description is given of some actual tests performed on a very large interconnected system with a 250-mi. transmission loop, involving five power companies and a total generator capacity well over 1,000,000 kw. The results of these measurements are analyzed for the purpose of checking theoretical against actual values and forming a basis for the solution of problems of a similar nature.

Controlling Power Flow with Phase Shifting Equipment

Calculating Probability of Generating Capacity Outages

A GROUP of 132-kv and 66-kv transmission systems form a loop about 300 miles in circumference and connect many important generating stations and a number of load points in the western part of Pennsylvania and the eastern portion of Ohio.

W. J. Lyman

Papers

Controlling Power Flow with Phase Shifting Equipment

Calculating Probability of Generating Capacity Outages

Application of Large Phase-Shifting Transformer on an Interconnected System Loop