Apparatus and method for fast vacuum switch link
An apparatus and methods of opening and closing a vacuum switched link are disclosed. The apparatus includes a vacuum interrupter including a mechanical coupling and a moving contact. The apparatus further includes a drive rod, where the mechanical coupling is disposed between the drive rod and the moving contact. The apparatus further includes a direct-acting closing spring coupled to the drive rod. The apparatus further includes a reset spring coupled to the drive rod. The apparatus further includes an armature slidably coupled to the drive rod and responsive to the reset spring during closing of the vacuum interrupter. The apparatus further includes a coil embedded in the armature.
1 . An apparatus, comprising:
a vacuum interrupter comprising a mechanical coupling and a moving contact;
a drive rod, wherein the mechanical coupling is disposed between the drive rod and the moving contact;
a direct-acting closing spring coupled to the drive rod;
a reset spring coupled to the drive rod;
an armature slidably coupled to the drive rod and responsive to the reset spring during closing of the vacuum interrupter; and
a coil embedded in the armature;
wherein:
contact load of the vacuum interrupter is in a range of 6,000-10,000 newtons; or
a rated current of the vacuum interrupter is in a range of 1,800-5,400 amperes; or
when the coil is de-energized, the drive rod is accelerated upward to close the vacuum interrupter, wherein time to close the vacuum interrupter is in a range of 18-22 milliseconds.
2 . The apparatus of claim 1 wherein a first portion of the drive rod comprises an insulating material.
3 . The apparatus of claim 2 wherein the first portion of the drive rod is coupled to a second portion of the drive rod comprising stainless steel.
4 . The apparatus of claim 3 further comprising an anti-rotation disc coupled to the second portion of the drive rod, to reduce effect of torque generated during a linear expansion or contraction of the direct-acting closing spring and the reset spring.
5 . The apparatus of claim 1 wherein the vacuum interrupter further comprises a moving contact stem mechanically coupled to a bellows, wherein a portion of a vacuum enclosure of the vacuum interrupter includes the bellows.
6 . The apparatus of claim 1 wherein the vacuum interrupter further comprises a fixed contact and a moving contact, the fixed contact being spaced apart from the moving contact by a distance in a range of 4-8 millimeters (mm) when the vacuum interrupter is in an open position.
7 . The apparatus of claim 1 wherein the vacuum interrupter remains open when a holding current is applied to the coil.
8 . The apparatus of claim 1 further comprising an actuator coupled to the mechanical coupling of the vacuum interrupter, wherein the vacuum interrupter is closed when the actuator is de-energized.
9 . The apparatus of claim 1 further comprising an actuator coupled to the mechanical coupling of the vacuum interrupter, wherein the vacuum interrupter is open when the actuator is energized.
10 . The apparatus of claim 1 wherein travel of the direct-acting closing spring is same as a closing distance of the vacuum interrupter.
11 . The apparatus of claim 1 wherein travel of the reset spring is same as travel of the armature with respect to the drive rod.
12 . The apparatus of claim 1 further comprising shock absorbers coupled to the drive rod, to retard closing speed of the vacuum interrupter.
13 . The apparatus of claim 1 wherein when the coil is energized, an attractive magnetic force is applied between the armature and an armature base plate to open the vacuum interrupter.
14 . The apparatus of claim 13 wherein time to open the vacuum interrupter is in a range of 5-25 milliseconds.
15 . A method of opening a vacuum switched link having a vacuum interrupter, a drive rod, a direct-acting closing spring, a reset spring, and an armature having a coil embedded therein, the vacuum interrupter comprising a moving contact coupled to the drive rod, the drive rod further coupled to the direct-acting closing spring and the reset spring, and the armature slidably coupled to the drive rod, the method comprising:
applying a pulse of current to the coil to open the vacuum interrupter, wherein the pulse of current applied to the coil generates an attractive magnetic force between the armature and an armature base plate that overcomes closing forces applied by the direct-acting closing spring and the reset spring;
applying a holding current to the coil; and
applying a constant resultant force to the drive rod, the constant resultant force comprising the closing forces exerted by the direct-acting closing spring and the reset spring, and a dominant opening force exerted by the armature due to the holding current applied to the coil;
wherein:
contact load of the vacuum interrupter is in a range of 6,000-10,000 newtons; or
a rated current of the vacuum interrupter is in a range of 1,800-5,400 amperes; or
when the coil is de-energized, the drive rod is accelerated upward to close the vacuum interrupter, wherein time to close the vacuum interrupter is in a range of 18-22 milliseconds.
16 . A method of closing a vacuum switched link having a vacuum interrupter, a drive rod, a direct-acting closing spring, a reset spring, and an armature having a coil embedded therein, the vacuum interrupter comprising a moving contact coupled to the drive rod, the drive rod further coupled to the direct-acting closing spring and the reset spring, and the armature slidably coupled to the drive rod, the method comprising:
quenching a holding current flowing in the coil;
allowing unrestricted acceleration of the armature for a reset distance, driven by the reset spring, to accelerate closure of the vacuum interrupter; and
applying forces to the drive rod including a closing force exerted by the direct-acting closing spring and another closing force exerted by the reset spring;
wherein:
contact load of the vacuum interrupter is in a range of 6,000-10,000 newtons; or
a rated current of the vacuum interrupter is in a range of 1,800-5,400 amperes; or
when the coil is de-energized, the drive rod is accelerated upward to close the vacuum interrupter, wherein time to close the vacuum interrupter is in a range of 18-22 milliseconds.