Protective system for series capacitors

Claim 2

In a series capacitor installation having a capacitor adapted to be connected in series in an alternating current line, a protective spark gap device and bypass switch means connected across said capacitor, control means for said bypass switch including a pneumatic cylinder for actuating the switch, first spring means for biasing the switch to closed position, valve means for admitting air to said cylinder to actuate the switch to open position, pneumatic latch means for latching the switch in open position, said latch means being actuated to latching position in response to movement of the switch to open position, and meanS responsive to predetermined conditions of said installation for effecting operation of the latch means to release the switch to move to closed position.

Claim 3

The combination of claim 1 in which said pneumatic latch means comprises at least one latch cylinder, a latch member movable in said latch cylinder to and from latching position, second spring means for biasing the latch member in one direction of movement, and means for admitting air to the latch cylinder to effect movement of the latch member in the opposite direction.

Claim 4

The combination of claim 2 in which said second spring means biases the latch member to the release position, and the latch member is moved to the latching position by air pressure.

Claim 5

In combination, a switch device having a movable contact, actuating means for said movable contact, a pneumatic cylinder, said actuating means including an actuating member movable in said cylinder, first spring means biasing said actuating member in one direction, means for admitting air to said cylinder to move the actuating member in the opposite direction, latching means for said actuating member comprising at least one latch cylinder and a latch member movable in the latch cylinder between latching and released positions and adapted to engage the actuating member in the latched position, second spring means biasing said latch member to one of said positions, means for admitting air to the latch cylinder to move the latch to the other of said positions, and means actuated in response to movement of said actuating member for admitting air to the latch cylinder when the actuating member reaches a predetermined position.

Claim 6

In combination, a switch device having a movable contact, actuating means for said movable contact, a pneumatic cylinder, said actuating means including an actuating member movable in said cylinder, first spring means biasing said actuating member in one direction, means for admitting air to said cylinder to move the actuating member in the opposite direction, latching means for said actuating member comprising at least one latch cylinder and a latch member movable in the latch cylinder between latching and released positions and adapted to engage the actuating member in the latched position, second spring means biasing said latch member to one of said positions, means for admitting air to the latch cylinder to move the latch to the other of said positions, and means actuated in response to movement of said actuating member for admitting air to the latch cylinder when the actuating member reaches a predetermined position.

Claim 7

The combination of claim 4 in which the spring means biases the latch member to the released position and air pressure admitted to the latch cylinder moves the latch member to the latching position and holds it in latching position.

Claim 8

A series capacitor installation comprising a capacitor bank adapted to be connected in series in an alternating current transmission line, a combined protective spark gap device and bypass switch means connected across said capacitor, first spring means biasing said switch means to closed position, a pneumatic cylinder for actuating said switch means to open position, latching means including at least one latch cylinder, a latch member movable in the latch cylinder to latching position to latch the switch means in open position, second spring means biasing the latch member to released position to release the switch means, means for supplying an air blast to said gap device and bypass switch means, valve means for admitting air to said pneumatic cylinder to actuate the switch means to open position and for applying said air blast, means responsive to actuation of the switch means to open position for admitting air to said latch cylinder to latch the switch means and for shutting off the air blast, and means responsive to predetermined conditions of the series capacitor installation for effecting exhaust of air from said latch cylinder to permit the latch member to move to released position to release the switch means to move to closed position.

Claim 9

A series capacitor installation comprising a capacitor bank adapted to be connected in series in an alternating current transmission line, a combined protective spark gap device and bypass switch means connected across said capacitor, first spring means biasing said switch means to closed position, a pneumatic cylinder for actuating said switch means to open position, latching means including at least one latch cylinder, a latch member movable in the latch cylinder to latching position to latch the switch means in open position, second spring means biasing the latch member to released position to release the switch means, means for supplying an air blast to said gap device and bypass switch means, valve means for admitting air to said pneumatic cylinder to actuate the switch means to open position and for applying said air blast, means responsive to actuation of the switch means to open position for admitting air to said latch cylinder to latch the switch means and for shutting off the air blast, and means responsive to predetermined conditions of the series capacitor installation for effecting exhaust of air from said latch cylinder to permit the latch member to move to released position to release the switch means to move to closed position.

Claim 10

A series capacitor installation as defined in claim 6 and including means responsive to current flow through said gap devices for applying said air blast and for effecting exhaust of air from the latch cylinder after a predetermined time delay.

Claim 11

A series capacitor installation as defined in claim 6 in which said predetermined conditions of the installation include overvoltage across the capacitor for more than a predetermined time, overtemperature of the capacitor, and electrical unbalance of the capacitor.