Low energy reclosing pulse test

Patent metadata

Field	Value
Publication number	US-2021175033-A1
Application number	US-202017109015-A
Country	US
Kind code	A1
Filing date	Dec 1, 2020
Priority date	Dec 5, 2019
Publication date	Jun 10, 2021
Grant date	—

Abstract

A method for performing a low energy pulse testing in a power distribution network that causes contacts to close and then open in about one fundamental frequency cycle of current flow time and close on a voltage waveform that produces symmetrical fault current. The method includes energizing a magnetic actuator to move the actuator against the bias of a spring to move a movable contact towards a fixed contact. The method also includes de-energizing the actuator when the movable contact makes contact with the fixed contact so as to allow the spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts is about one fundamental frequency cycle of the current, where energizing the magnetic actuator occurs when an applied voltage on the switch assembly is at a peak of the voltage wave so that the current is symmetric.

First claim

What is claimed is:

1 . A method for operating a magnetically actuated switch assembly to perform a low energy test pulse, the switch assembly including a fixed contact and a movable contact, the method comprising:
energizing a magnetic actuator to move the actuator against the bias of at least one spring coupled to the movable contact towards the fixed contact to make contact therebetween, wherein AC current conducts across a gap between the movable contact and the fixed contact before the movable contact and the fixed contact make contact; and de-energizing the magnetic actuator or reversing the voltage on the magnetic actuator when the movable contact makes contact with the fixed contact so as to allow the bias of the at least one spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts between the movable contact and the fixed contact is about one fundamental frequency cycle of the current, wherein energizing the magnetic actuator occurs at a time so that when the movable contact and the fixed contact begin conducting an applied voltage on the switch assembly is at or near a peak of the voltage wave so that the current is symmetric.

2 . The method according to claim 1 wherein the at least one spring is a larger open spring and a smaller compliance spring.

3 . The method according to claim 2 wherein the open spring is wrapped around a cylindrical housing and the compliance spring is provided within the housing.

4 . The method according to claim 3 wherein the magnetic actuator includes a stationary core having a coil and a movable core that moves towards the stationary core when the actuator is energized, and wherein de-energizing the magnetic actuator or reversing the voltage on the magnetic actuator includes include removing or reversing a voltage applied to the coil.

5 . The method according to claim 1 wherein the one fundamental frequency cycle of current is about 16.7 ms for 60 Hz.

6 . The method according to claim 5 wherein the time that the contacts begin conducting to the time the contacts will withstand voltage when the current goes to zero is about three-quarters of the one fundamental frequency cycle time.

7 . The method according to claim 1 wherein the voltage on the switch assembly that is at or near the peak of the voltage wave is at a 90° voltage angle.

8 . The method according to claim 1 wherein the contacts are part of a vacuum interrupter.

9 . The method according to claim 8 wherein the current is a fault current in a medium voltage power distribution network and the vacuum interrupter is part of a recloser in the power distribution network.

10 . A method for performing a reclosing fault testing operation in a power distribution network using a vacuum interrupter including a fixed contact and a movable contact, the method comprising:
energizing a magnetic actuator to move the actuator against the bias of at least one spring coupled to the movable contact towards the fixed contact to make contact therebetween, wherein AC fault current conducts across a gap between the movable contact and the fixed contact before the movable contact and the fixed contact make contact; and de-energizing the magnetic actuator or reversing the voltage on the magnetic actuator when the movable contact makes contact with the fixed contact so as to allow the bias of the at least one spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts between the movable contact and the fixed contact is about one fundamental frequency cycle of the fault current.

11 . The method according to claim 10 wherein the one fundamental frequency cycle of current is about 16.7 ms for 60 Hz.

12 . The method according to claim 11 wherein the time that the contacts begin conducting to the time the contacts will withstand voltage when the current goes to zero is about three-quarters of the one fundamental frequency cycle time.

13 . The method according to claim 10 wherein the at least one spring is a larger open spring and a smaller compliance spring.

14 . A method for performing a low energy pulse testing operation in a power distribution network using a vacuum interrupter including a fixed contact and a movable contact, the method comprising:
energizing a magnetic actuator to move the actuator against the bias of at least one spring coupled to the movable contact towards the fixed contact to make contact therebetween, wherein AC fault current conducts across a gap between the movable contact and the fixed contact before the movable contact and the fixed contact make contact; and de-energizing the magnetic actuator or reversing the voltage on the magnetic actuator so as to allow the bias of the at least one spring to move the movable contact away from the fixed contact, wherein energizing the magnetic actuator occurs at a time so that when the movable contact and the fixed contact begin conducting an applied voltage on the switch assembly is at or near a peak of the voltage wave so that the fault current is symmetric.

15 . The method according to claim 14 wherein the voltage on the switch assembly that is at or near the peak of the voltage wave is at a 90° voltage angle.

16 . The method according to claim 14 wherein the at least one spring is a larger open spring and a smaller compliance spring.

17 . A system for using a magnetically actuated switch assembly to produce a low energy pulse test, the switch assembly including a fixed contact and a movable contact, the system comprising:
means for energizing a magnetic actuator to move the actuator against the bias of at least one spring coupled to the movable contact towards the fixed contact to make contact therebetween, wherein AC current conducts across a gap between the movable contact and the fixed contact before the movable contact and the fixed contact make contact; and means for de-energizing the magnetic actuator or reversing the voltage on the magnetic actuator when the movable contact makes contact with the fixed contact so as to allow the bias of the at least one spring to move the movable contact away from the fixed contact so that the amount of time that the current conducts between the movable contact and the fixed contact is about one fundamental frequency cycle of the current, wherein energizing the magnetic actuator occurs at a time so that when the movable contact and the fixed contact begin conducting an applied voltage on the switch assembly is at or near a peak of the voltage wave so that the current is symmetric.

18 . The system according to claim 17 wherein the one fundamental frequency cycle of current is about 16.7 ms for 60 Hz.

19 . The system according to claim 18 wherein the time that the contacts begin conducting to the time the contacts will withstand voltage when the current goes to zero is about three-quarters of the one fundamental frequency cycle time.

20 . The method according to claim 17 wherein the voltage on the switch assembly that is at or near the peak of the voltage wave is at a 90° voltage angle.

Assignees

• S & C Electric Co

Inventors

• Porter David G
• Williams Stephen E
• Meyer Peter J
• Bishop Martin T
• Dyer Thomas J
• Berman Andrew B
• Milton Joseph W
• Abramczyk Lauren

Classifications

• H01H33/006

  adapted for interrupting fault currents with delayed zero crossings · CPC title

• G01R31/3271

  of high voltage or medium voltage devices (G01R31/333 takes precedence) · CPC title

• H01H33/6662 Primary

  using bistable electromagnetic actuators, e.g. linear polarised electromagnetic actuators · CPC title

• G01R31/3278 Primary

  of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002) · CPC title

• H01H36/00

  Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding · CPC title