Capacitor voltage transformers

X6/1987 Measuring voltage transformers Protective voltage transformers Capacitor voltage transformers. "1156-2/1992. 1156-3/1992 3156-4/1992 BS 7729/1995 BS 7625/1993 ... 

The size and therefore the cost of a conventionally wound voltage transformer will be almost proportional to the system voltage for which it is wound. As a cost consideration, therefore, a more economical alternative is found in a Capacitor Voltage Transformer (CVT) (Figure 15.6(a)). 

Figure 15.6(a) Capacitor voltage transformer (CVT) rated voltage 36-420 kV and above (Courtesy ABB)... 

Figure 18.13 A transformer as a capacitor voltage divider, drawn for one phase...

This method is applicable to single-star or delta-connected capacitor banks. Unbalance can be detected through the use of an RVT (residual voltage transformer) (Section 15.4.3). See Figure 26.4. The theory of operation is that any unbalance, of the system or the capacitor bank, will shift the neutral and reflect as the residual voltage across the open delta and can be used for the protective scheme. The unbalance voltage across the open delta in the event of failure of a unit in any series group can be expressed by... 

FIGURE 37.1 Typical magnetic stimulation circuit, including high-voltage transformer, capacitor, resistor, thyristor trigger, and stimulating coil. 

Voltage analysis starts with a correct representation, or map, of the feeder circuits, starting at the substation. The map generally consists of details and electrical characteristics (e.g., kilovoltampere rating, impedance, etc.) of the conductors and cables on the system, substation and distribution transformers, series and shunt capacitors, voltage regulators, etc. 

FIGURE 14 Voltage transformers (VT) (a) Capacitor VT and (b) cascade connected VT. [From Gregory, B. A. (1981). An Introduction to Electrical Instrumentation and Measurement Systems, Macmillan Education, Hampshire, England.]... 

Power Supplies and Controls. Induction heating furnace loads rarely can be connected directiy to the user s electric power distribution system. If the load is to operate at the supply frequency, a transformer is used to provide the proper load voltage as weU as isolation from the supply system. Adjustment of the load voltage can be achieved by means of a tapped transformer or by use of a solid-state switch. The low power factor of an induction load can be corrected by installing a capacitor bank in the primary or secondary circuit. 

Xj = Xl the circuit would behave like a normal transformer Voltage drop across the line capacitors Vl Voltage drop across the inductance... 

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