摘要:
Automatically changing the tap position in a load tap changer includes noting a polarity of a first tap position of a load tap changer. A duration for which one or more consecutive tap positions of the load tap changer collectively have had the noted polarity also is noted. The one or more consecutive tap positions include the first tap position. The duration for which the one or more consecutive tap positions collectively have had the noted polarity is compared to a threshold value. A change is made from the first tap position to a second tap position with a polarity that is different than the noted polarity when the duration for which the one or more consecutive tap positions collectively have had the noted polarity is longer than the threshold value. A change may be made from the second tap position back to the first tap position.
摘要:
The life of load tap changer contacts is monitored by detecting an arcing event; identifying arcing surfaces involved in the arcing event; calculating a per-unit loss of life for the identified arcing surfaces as a result of the arcing event; updating estimates of cumulative erosion for the arcing surfaces; comparing the updated estimates of cumulative erosion to a first threshold value; and signaling for action when at least one of the updated estimates of cumulative erosion exceeds the first threshold value.
摘要:
A position indicator may include a position indicator display and mechanism. A polymer housing houses the position indicator display and mechanism and a one-piece clear polymer cover encloses the position indicator display and mechanism in the polymer housing. The position indicator may further include a hinge and hand-operated latch that secures the one-piece clear polymer cover to the polymer housing such that the one-piece clear polymer cover can be opened without the use of tools.
摘要:
A position indicator may include a position indicator display and mechanism. A polymer housing houses the position indicator display and mechanism and a one-piece clear polymer cover encloses the position indicator display and mechanism in the polymer housing. The position indicator may further include a hinge and hand-operated latch that secures the one-piece clear polymer cover to the polymer housing such that the one-piece clear polymer cover can be opened without the use of tools.
摘要:
A preventive maintenance tapping technique includes noting a tap position of a load tap changer and noting a duration that the tap position has been held. The duration that the tap position has been held is compared to a threshold value, and the tap position is changed if the tap position has been held for longer than the threshold value. Similarly, a duty cycle monitoring technique for monitoring life of load tap changer contacts includes detecting an arcing event. Arcing surfaces involved in the arcing event are identified and the effects of the arcing event on the arcing surfaces are calculated. Estimates of the erosion on the arcing surfaces are updated, and the estimates are compared to a threshold value. A signal for maintenance is generated when the estimate exceeds the threshold value.
摘要:
The life of load tap changer contacts is monitored by detecting an arcing event; identifying arcing surfaces involved in the arcing event; calculating a per-unit loss of life for the identified arcing surfaces as a result of the arcing event; updating estimates of cumulative erosion for the arcing surfaces; comparing the updated estimates of cumulative erosion to a first threshold value; and signaling for action when at least one of the updated estimates of cumulative erosion exceeds the first threshold value.