Series capacitor equipment
First Claim
1. Series capacitor equipment for connection into an electric power supply network, comprising:
- a capacitor bank;
a varistor coupling connected in parallel with the capacitor bank for protection of the latter against overvoltages, the varistor coupling including first and second parallel branches;
wherein the first branch includes a first metal oxide varistor having a first "knee" voltage in series with a first resistor; and
wherein the second branch includes a second varistor having a second "knee" voltage;
the second "knee" voltage of the second varistor being at least 1.15 times the first "knee" voltage of the first varistor, andthe first resistor having a considerably lower degree of voltage dependence than the first varistor.
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Accused Products
Abstract
A series capacitor bank for connection into an electric power supply network is provided with overvoltage protective equipment having two branches connected in parallel with the capacitor bank. The first branch comprises a first zinc oxide varistor in series with a linear resistor and the second branch comprises a varistor with a higher "knee" voltage than the first zinc oxide varistor. The resistance of the linear resistor is preferably of the same order of magnitude as the absolute value of the impedance of the capacitor bank at the operating frequency of the power supply network. The "knee" voltage of the second varistor is at least 1.15 times (and preferably not more than 2.0 times) the "knee" voltage of the first varistor.
60 Citations
15 Claims
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1. Series capacitor equipment for connection into an electric power supply network, comprising:
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a capacitor bank; a varistor coupling connected in parallel with the capacitor bank for protection of the latter against overvoltages, the varistor coupling including first and second parallel branches; wherein the first branch includes a first metal oxide varistor having a first "knee" voltage in series with a first resistor; and wherein the second branch includes a second varistor having a second "knee" voltage; the second "knee" voltage of the second varistor being at least 1.15 times the first "knee" voltage of the first varistor, and the first resistor having a considerably lower degree of voltage dependence than the first varistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification