The capacitive voltage divider is composed of the high-voltage capacitor C1 and the medium-voltage capacitor C2. The electromagnetic unit includes the compensation reactor LC, the intermediate transformer T, and the damper Zf. The damper can be connected to any one of the secondary windings. Fig 1. Structure of the CVT system.
The theoretical results were confirmed by measurements on two 500 kV and one 800 kV compressed gas capacitors [44, 45]. Typical values of the measured natural frequency ranged from f0 = 52 Hz for a 120 kV capacitor of 50 pF down to f0 = 8 Hz for an 800 kV capacitor of 68 pF.
Above: relative change in capacitance C, Below: relative change in tan δ In summary, it can be stated that the investigated nine compressed gas capacitors with rated voltages of 100–800 kV have electrical resonance frequencies between 26 and 4 Hz, which are thus well below the usual power frequencies of 50–60 Hz.
Using the method presented in Section 2 of this paper, a harmonic equivalent circuit is established for this 35-kV CVT, and the parameters of the circuit components are obtained. The three resonant frequencies of the harmonic equivalent circuit are calculated as follows: f1 = 2.88 Hz, f2 = 525.55 Hz and f3 = 646.96 Hz.
Use calculator-2 when capacitor voltage, capacitive reactance, and frequency are known. Also on this page are calculators (calculator-3 and calculator-4) for applying capacitors on systems that deviate from their nameplate rating. Use these calculators to determine resulting output kvar and current for your specific application.
Typical values of the measured natural frequency ranged from f0 = 52 Hz for a 120 kV capacitor of 50 pF down to f0 = 8 Hz for an 800 kV capacitor of 68 pF. Figure 11.14 shows examples of the recorded current i (t) of the capacitors after being excited by a mechanical impulse.