The continuously increasing demand for electric power and the economic access to remote renewable energy sources such as off-shore wind power or solar thermal generation in deserts have revived the interest in high-voltage direct current (HVDC) multiterminal systems (networks). A lot of work was done in this area, especially in the 1980s, but only two three-terminal systems were realized. Since then, HVDC technology has advanced considerably and, despite numerous technical challenges, the realization of large-scale HVDC networks is now seriously discussed and considered. For the acceptance and reliability of these networks, the availability of HVDC circuit breakers (CBs) will be critical, making them one of the key enabling technologies. Numerous ideas for HVDC breaker schemes have been published and patented, but no acceptable solution has been found to interrupt HVDC short-circuit currents. This paper aims to summarize the literature, especially that of the last two decades, on technology areas that are relevant to HVDC breakers. By comparing the mainly 20+ years old, state-of-the art HVDC CBs to the new HVDC technology, existing discrepancies become evident. Areas where additional research and development are needed are identified and proposed.

HVDC Circuit Breakers: A Review Identifying Future Research Needs

A survey is presented of papers and reports that address various aspects of economic dispatch. The time period considered is 1977-88. Four related areas of economic dispatch are identified and papers published in the general areas of economic dispatch are classified into these. These areas are: optimal power flow, economic dispatch in relation to AGC, dynamic dispatch, and economic dispatch with nonconventional generation sources. >

/pdf/a-review-of-recent-advances-in-economic-dispatch-enueg8mqmk.pdf

A review of recent advances in economic dispatch

The paper reviews literature which addresses the application of Flexible AC Transmission System (FACTS) concepts to the improvement of Power System utilisation and performance. It summarises literature on using high speed thyristor based control of HVAC power system elements to enhance the power carrying capacity of existing transmission circuits without compromising reliability. It describes a study system representative of existing power systems that has been developed to evaluate the economic and technical issues of loading transmission lines to their thermal limits. Considered are two scenarios, a multi-line corridor and a long radial interconnection, where the issues addressed are transient and dynamic stability, power flow control, reactive support and voltage stability. A benchmark system is developed to validate performance of die more simple devices. It is concluded that FACTS devices have the potential to significantly increase system stability margins thereby increasing loading capabil...

Flexible AC transmission systems (FACTS)

In this paper an extensive literature review on load–frequency control (LFC) problem in power system has been highlighted. The various configuration of power system models and control techniques/strategies that concerns to LFC issues have been addressed in conventional as well as distribution generation-based power systems. Further, investigations on LFC challenges incorporating storage devices BESS/SMES, FACTS devices, wind–diesel and PV systems etc have been discussed too.

A literature survey on load–frequency control for conventional and distribution generation power systems

Engineers in the power industry, face the problem that, while stability is increasingly a limiting factor in secure system operation, the simulation of system dynamic response is grossly overburdening on present-day digital computing resources. Each individual response case involves the step-by-step numerical solution in the time domain of perhaps thousands of nonlinear differential-algebraic equations, at a cost of up to several thousand dollars. A high premium is thus to be placed on the use of the most efficient and reliable modern calculation techniques. This paper is a critical tutorial-review of the calculation methods used routinely or investigated for use by the industry. It concentrates on solution concepts and computational techniques rather than on the analysis of the numerical methods. Details of system modeling are only emphasized when they affect the choice of solution method. The paper concludes with a view of the state of the art and a prediction of future directions of development.

Power system dynamic response calculations

A study was made of the accuracy of utility power system stability simulations, as affected by the complexity of the synchronous generator models and the data used with the models. The investigation was performed by simulating the operation of a representative multimachine power system with many combinations of disturbance, initial load, system stiffness, model detail and model data. The findings from this study provide guidelines for the selection of the simplest computational machine models for use in large scale stability analyses, with the goal of minimizing the cost of computer usage while assuring sufficient accuracy of the results. Recommendations are made for selecting machine data more suitable for use in stability studies than the standard machine data.

Effects of Synchronous Machine Modeling in Large Scale System Studies

Basin Electric Power Cooperative will commission a Static Var System (SVS) in late 1977 to provide automatic, continuous voltage control on a 115 kV network in western Nebraska. This paper describes engineering studies which were conducted to select the SVS rating and site, determine harmonic filtering requirements, synthesize the SVS voltage regulator characteristics and to simulate the steady-state and dynamic performance of the SVS. The studies have shown that the SVS will perform as intended to regulate the steady-state voltage within ±0.5% and reduce post-fault voltage swings which otherwise might cause important motor loads to trip off line.

Application of a Static VAR System to Regulate System Voltage in Western Nebraska

The specific role of Static Var Systems (SVS) as a form of dynamic reactive power compensation in high voltage ac power systems is described. A characteristic of the SVS which sets it apart from other forms of compensation is its extreme speed of response in adjusting its reactive power output to meet rapidly changing needs of the system. Examples [1] are given showing the benefits of SVS in suppressing load rejection overvoltages, increasing the transient stability power limit of a 500 kV radial transmission system, and in preventing a voltage collapse following a generator trip and subsequent increase in import power requirements. One example shows how the installation of a third 500 kV circuit could be avoided with the application of two SVS, with a significant savings in capital costs.

The Role and Benefits of Static Var Systems in High Voltage Power System Applications

This paper reviews certain vital control functions central to the practical implementation of parallel multiterminal do (MTDC) systems. Particularly, the requirements for coordination of current orders during different operating conditions of MTDC systems are discussed. Two new techniques of current order coordination are described. The two techniques are referred to in this paper as the Modulation Coordination and the Decentralized Current Reference Balancer (DCRB).

Current Order Coordination in Miltiterminal DC Systems

This paper addresses the simply stated but important question: If a utility has decided to install a number of arrays of wind turbine (WT) generators, how should they be operated and controlled on the load frequency control time-scale- seconds to minutes?

R. L. Hauth

Papers

Effects of Synchronous Machine Modeling in Large Scale System Studies

Application of a Static VAR System to Regulate System Voltage in Western Nebraska

The Role and Benefits of Static Var Systems in High Voltage Power System Applications

Current Order Coordination in Miltiterminal DC Systems

A Method for Determining How to Operate and Control Wind Turbine Arrays in Utility Systems