Hence, all of these subjects can be explored in more detail in the upcoming chapters in this section. Control and operation are covered in Chapter 8, Power System Operation and Control. Voltage control is done automatically by generators, transformers, reactors, and capacitors, but the operator can remotely set the target voltages. For example, remote operation of circuit breakers can be manually initiated by operators through the supervisory control and data acquisition (SCADA) system at the control center. Many other types of control are also used for the normal and emergency operations of the power system. Protection system details are covered in Chapter 9, Power System Protection. In its most sophisticated form, microprocessor-based relays can detect the fault and analyze which circuit breakers need to be opened to isolate the equipment. In its simplest form, a fuse detects the fault by burning out and thus isolating the line. The general principle is to detect the fault (the short circuit) and isolate the equipment. Protecting all the equipment-generators, transformers, transmission lines, and distribution feeders-against short circuits is essential. A spare cylinder is usually carried to ensure continuity of supply should the first cylinder become exhausted.Īnjan Bose, in The Electrical Engineering Handbook, 2005 2.2.2 Protection and Control This is usually arranged by fitting a high pressure gas cylinder with a reducing valve to one of the tank filter valves and setting this to produce a slow gas-flow sufficient to make good the leakage from the tank flanges.
If the tank has been drained for transport, it is necessary for the oil to be replaced by either dry air or nitrogen, which must then be maintained at a slight positive pressure above the outside atmosphere to ensure that the windings remain as dry as possible whilst the oil is absent. For the other large transformers (station and unit transformers), it is usually only necessary to ship these without oil to ensure that they are comfortably within the appropriate transport limits, although it is necessary to check that when mounted on the transport vehicle the height is within the over-bridge clearances which, for trunk roads within the United Kingdom, allows a maximum travelling height of 4.87 m (sixteen feet).
SAG STEAM ACCOUNT GENERATOR GENERATOR
(The other two being the generator stator and the stator frame.) Transport considerations will therefore have a considerable bearing on the generator transformer design and more will be said on this subject in Section 2.2 of this chapter which deals specifically with generator transformers.
The generator transformer is usually one of the three largest and heaviest single loads to be delivered to a power station site. In Electrical Systems and Equipment (Third Edition), 1992 1.8.1 Transport
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