Principle of Generation, Transmission and Distribution of High Ac Voltages
PRINCIPLE OF GENERATION, TRANSMISSION AND DISTRIBUTION OF HIGH AC VOLTAGES
INTRODUCTION
The potential benefits of electrical energy supplied to a number of consumers from a common generating system were recognized shortly after the development of the ‘dynamo’, commonly known as the generator. The first public power station was put into service in 1882 in London (Holborn). Soon a number of other public supplies for electricity followed in other developed countries. The early systems produced direct current at low-voltage, but their service was limited to highly localized areas and was used mainly for electric lighting. The limitations of d.c. transmission at low voltage became readily apparent. By 1890 the art in the development of an a.c. generator and transformer had been perfected to the point when a.c. supply was becoming common, displacing the earlier d.c. system. The first major a.c. power station was commissioned in 1890 at Deptford, supplying power to central London over a distance of 28 miles at 10 000 V. From the earliest ‘electricity’ days it was realized that to make full use of economic generation the transmission network must be tailored to production with increased interconnection for pooling of generation in an integrated system. In addition, the potential development of hydroelectric power and the need to carry that power over long distances to the centers of consumption were recognized. Power transfer for large systems, whether in the context of interconnection of large systems or bulk transfers, led engineers invariably to think in terms of high system voltages. A power plant produces electrical energy in medium (20 000 V) or low (1 000 V) voltage which is then elevated to high voltage (up to 400 kV) by a step-up substation. Electrical power is then transmitted across long distances by high-tension power lines, and the higher the voltage, the more power can be transmitted. A step-down substation converts the high voltage back
INTRODUCTION
The potential benefits of electrical energy supplied to a number of consumers from a common generating system were recognized shortly after the development of the ‘dynamo’, commonly known as the generator. The first public power station was put into service in 1882 in London (Holborn). Soon a number of other public supplies for electricity followed in other developed countries. The early systems produced direct current at low-voltage, but their service was limited to highly localized areas and was used mainly for electric lighting. The limitations of d.c. transmission at low voltage became readily apparent. By 1890 the art in the development of an a.c. generator and transformer had been perfected to the point when a.c. supply was becoming common, displacing the earlier d.c. system. The first major a.c. power station was commissioned in 1890 at Deptford, supplying power to central London over a distance of 28 miles at 10 000 V. From the earliest ‘electricity’ days it was realized that to make full use of economic generation the transmission network must be tailored to production with increased interconnection for pooling of generation in an integrated system. In addition, the potential development of hydroelectric power and the need to carry that power over long distances to the centers of consumption were recognized. Power transfer for large systems, whether in the context of interconnection of large systems or bulk transfers, led engineers invariably to think in terms of high system voltages. A power plant produces electrical energy in medium (20 000 V) or low (1 000 V) voltage which is then elevated to high voltage (up to 400 kV) by a step-up substation. Electrical power is then transmitted across long distances by high-tension power lines, and the higher the voltage, the more power can be transmitted. A step-down substation converts the high voltage back