10-07-2012, 11:01 AM
A Computer Based Study of Transmission Loss Evaluation
[attachment=27316]
RITU GROVER
This paper is concerned with the process of evaluating transmission losses as proposed by O.I. Elgard, Kron and Yung-Chung Chang. Wei-Tzen Yang, Chun-chun Lui. Computer programmes were prepared on these methods and subsequently compared on a standard four-bus system. Transmission loss considerations have often proved to be important in the planning of future systems in particular regard to location of plants and the construction of transmission lines. Computers have brought a sea change in all walks of life including the operation, control and maintenance of power systems. The computing and analytical techniques are of increasing value ot the electric utility engineering since systems have tended to become progressively complex as they expand. Computer study was essential as the transmission loss evaluation using computers has facilities like reliability, accuracy, simplicity, directness, rapid execution and reduction in time. The losses are necessary to be determined as the cost of producing energy and as the price of installing new generating plants are increasing. By adopting suitable measures and control these losses can be diminished considerably.
Introduction
An engineer is always concerned with the cost of product and services. For a power system to return a profit on the capital invested, proper operation is always necessary. Rates fixed by regulatory bodies place extreme pressures on power companies to achieve maximum efficiency of operation and to improve efficiency continually in order to maintain a reasonable relation between cost of a kilowatt-hour in the face of constantly rising prices for fuel, labour, supplies an maintenance. [1].
With the development of power systems and the interconnections of companies for purposes of economy interchange, it is necessary to consider the incremental fuel costs along with the transmission losses. This consideration has resulted in the fuel savings upto one hundred dollars per year per megawatt. Another point in the operation of interconnected systems is the determination of transmission losses for the purposes of billing in various interconnections. The revenue to be gained by properly billing for these losses can be a very large sum. [2]. The advantage claimed in the equal transmission method is that the method requires only small computer memory, it is easy to make a programme of the method and sometimes, it is essential to develop a reliable algorithm also. This furnishes a flexible and accurate method of taking
Kron’s Method:
Kron’s circuit transformation (8) involves straightforward matrix operations. The first transformation expresses load currents in terms of generator current and second transformation expresses generator currents in terms of generator real power outputs.
The necessary assumption to achieve the first transformation to achieve the first transformation that the load current at any buss current be linearly related to total load current. The assumption for the second transformation is that the reactive output of the generator be linearly is related to its corresponding real power output.
Conclusion
Transmission loss was minimum when calculated through sensitivity factor and maximum when calculated using current distribution method. Kron’s method has proved to be better than current distribution method but is complicated, lengthy and time consuming as it applies transformation of frames of references.
The Sensitivity Factor Method avoids many limitations associated. The method is fast, linear and can handle line outages. The method avoids the use of complicated reference frame transformations based upon Kron’s analysis. The method is easy to implement and is well suited to on-line dispatch applications.
[attachment=27316]
RITU GROVER
This paper is concerned with the process of evaluating transmission losses as proposed by O.I. Elgard, Kron and Yung-Chung Chang. Wei-Tzen Yang, Chun-chun Lui. Computer programmes were prepared on these methods and subsequently compared on a standard four-bus system. Transmission loss considerations have often proved to be important in the planning of future systems in particular regard to location of plants and the construction of transmission lines. Computers have brought a sea change in all walks of life including the operation, control and maintenance of power systems. The computing and analytical techniques are of increasing value ot the electric utility engineering since systems have tended to become progressively complex as they expand. Computer study was essential as the transmission loss evaluation using computers has facilities like reliability, accuracy, simplicity, directness, rapid execution and reduction in time. The losses are necessary to be determined as the cost of producing energy and as the price of installing new generating plants are increasing. By adopting suitable measures and control these losses can be diminished considerably.
Introduction
An engineer is always concerned with the cost of product and services. For a power system to return a profit on the capital invested, proper operation is always necessary. Rates fixed by regulatory bodies place extreme pressures on power companies to achieve maximum efficiency of operation and to improve efficiency continually in order to maintain a reasonable relation between cost of a kilowatt-hour in the face of constantly rising prices for fuel, labour, supplies an maintenance. [1].
With the development of power systems and the interconnections of companies for purposes of economy interchange, it is necessary to consider the incremental fuel costs along with the transmission losses. This consideration has resulted in the fuel savings upto one hundred dollars per year per megawatt. Another point in the operation of interconnected systems is the determination of transmission losses for the purposes of billing in various interconnections. The revenue to be gained by properly billing for these losses can be a very large sum. [2]. The advantage claimed in the equal transmission method is that the method requires only small computer memory, it is easy to make a programme of the method and sometimes, it is essential to develop a reliable algorithm also. This furnishes a flexible and accurate method of taking
Kron’s Method:
Kron’s circuit transformation (8) involves straightforward matrix operations. The first transformation expresses load currents in terms of generator current and second transformation expresses generator currents in terms of generator real power outputs.
The necessary assumption to achieve the first transformation to achieve the first transformation that the load current at any buss current be linearly related to total load current. The assumption for the second transformation is that the reactive output of the generator be linearly is related to its corresponding real power output.
Conclusion
Transmission loss was minimum when calculated through sensitivity factor and maximum when calculated using current distribution method. Kron’s method has proved to be better than current distribution method but is complicated, lengthy and time consuming as it applies transformation of frames of references.
The Sensitivity Factor Method avoids many limitations associated. The method is fast, linear and can handle line outages. The method avoids the use of complicated reference frame transformations based upon Kron’s analysis. The method is easy to implement and is well suited to on-line dispatch applications.