Overvoltage protection for series capacitor equipment
First Claim
1. An overvoltage protection device for series capacitor equipment, comprising:
- a main spark gap with a first and a second main electrode for connection in parallel with a series capacitor, and adapted to be ignited at a predetermined level of the voltage across the series capacitor, comprising;
a series connection connected parallel to the main spark gap and including a first voltage-dependent impedance element with a predetermined knee voltage in which, when said predetermined knee voltage is exceeded, the impedance of the element drops, and a firing voltage-generating member which is adapted, upon an increase of the current through the first voltage-dependent impedance element to deliver a voltage for activating the spark gap of the overvoltage protective device;
a first auxiliary spark gap arranged adjacent to the main spark gap for ignition thereof, with a first electrode connected to the first main electrode of the main spark gap and a second electrode connected to the second main electrode of the main spark gap;
a second auxiliary spark gap arranged adjacent to the first auxiliary spark gap for ignition thereof, with a first main electrode connected to the first main electrode of the main spark gap and with a second main electrode connected to said firing voltage-generating member adapted to be supplied with said voltage for ignition of said second auxiliary spark gap;
wherein said second auxiliary spark gap is so designed that, upon ignition of this spark gap, the arc in the gap is driven by current forces in a direction towards said first auxiliary spark gap for ignition thereof;
wherein said first auxiliary spark gap is so designed that upon ignition of this first spark gap, the arc in the gap is driven by current forces in a direction towards the main spark gap for ignition thereof; and
wherein said second electrode of said first auxiliary spark gap is connected to said second main electrode of said main spark gap through a first resistor for discharge of said capacitor through said first auxiliary spark gap and said first resistor before ignition of the main spark gap.
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Accused Products
Abstract
An overvoltage protective device for a series capacitor (C) has a main spark gap and a first auxilary spark gap, arranged adjacent thereto, for ignition of the main spark gap. A second auxiliary spark gap is arranged in association with the first auxiliary gap for ignition thereof. The first and second auxiliary spark gaps are connected between one of the electrodes of the the main spark gap and a voltage divider which comprises resistors (R1, R2, R3 ) and a varisistor (VR1) . When the knee voltage of the varisistor is exceeded, the second auxiliary spark gap is ignited, the arc of which initiates ignition of the first auxiliary spark gap, the arc of which in turn moves towards and ignites the main spark gap. During the arcing time of the spark gap, a controlled discharge of the series capacitor through a resistor (R2) takes place.
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Citations
20 Claims
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1. An overvoltage protection device for series capacitor equipment, comprising:
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a main spark gap with a first and a second main electrode for connection in parallel with a series capacitor, and adapted to be ignited at a predetermined level of the voltage across the series capacitor, comprising; a series connection connected parallel to the main spark gap and including a first voltage-dependent impedance element with a predetermined knee voltage in which, when said predetermined knee voltage is exceeded, the impedance of the element drops, and a firing voltage-generating member which is adapted, upon an increase of the current through the first voltage-dependent impedance element to deliver a voltage for activating the spark gap of the overvoltage protective device; a first auxiliary spark gap arranged adjacent to the main spark gap for ignition thereof, with a first electrode connected to the first main electrode of the main spark gap and a second electrode connected to the second main electrode of the main spark gap; a second auxiliary spark gap arranged adjacent to the first auxiliary spark gap for ignition thereof, with a first main electrode connected to the first main electrode of the main spark gap and with a second main electrode connected to said firing voltage-generating member adapted to be supplied with said voltage for ignition of said second auxiliary spark gap; wherein said second auxiliary spark gap is so designed that, upon ignition of this spark gap, the arc in the gap is driven by current forces in a direction towards said first auxiliary spark gap for ignition thereof; wherein said first auxiliary spark gap is so designed that upon ignition of this first spark gap, the arc in the gap is driven by current forces in a direction towards the main spark gap for ignition thereof; and wherein said second electrode of said first auxiliary spark gap is connected to said second main electrode of said main spark gap through a first resistor for discharge of said capacitor through said first auxiliary spark gap and said first resistor before ignition of the main spark gap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification