A switch assembly has a switch; and a servo drive system for the switch. The servo drive system includes: a motor configured to drive the switch; a power section configured to supply power to the motor; and a control unit configured to control the power section depending on at least one desired value. The control unit is configured to identify the presence of at least one safety-relevant event and, in the case of the safety-relevant event, to transmit at least one control signal to the power section. The power section is configured to initiate or carry out at least one safety measure depending on the control signal.

A switch assembly including a switch and a drive system for the switch. The drive system includes a motor for driving the switch, a control device with a power section for supplying power to the motor, a controller for initiating a switching operation of the switch by control of the power section, and a protection circuit. The protection circuit is configured to detect a first error signal via a state contact of the controller in the event of a malfunction of the controller, detect a second error signal via a state contact of the power section in the event of a malfunction of the power section, and initiate a safety measure depending on the first and the second error signal. The control device is configured to activate the protection circuit prior to the switching operation being initiated and to deactivate it following successful execution of the switching operation.

A system for testing a transformer includes a voltage source configured to apply an input voltage to a secondary winding of the transformer, the input voltage is configured to induce a voltage in a primary winding of the transformer. A primary voltmeter is configured to measure the induced voltage in the primary winding, a plurality of secondary voltmeters configured to measure voltage in a plurality of secondary windings of the transformer, and one or more phase angle meters to simultaneously measure a plurality of phase angles between the primary voltage and each of the plurality of secondary voltages. A controller is connected to the voltage source, the primary voltmeter, the plurality of secondary voltmeters, and the one or more phase angle meters, the controller is configured to calculate a plurality of winding ratios based on the voltage and phase angle measurements, the controller is also configured to identify all secondary taps.

An on-load tap changer head includes: a first region for an insulating fluid of the on-load tap changer to flow; a second region separated from the first region by a wall; and a detector for detecting an increased flow speed of the insulating fluid. The detector includes: a flow flap in the first region configured to tilt from a defined flow speed of the insulating fluid from a first position to a second position; a first magnet secured to the flap such that in the second position of the flow flap, the first magnet is in an immediate vicinity of the wall; a second magnet in the second region in the immediate vicinity of the wall; and a switch in the second region that is operationally coupled to the second magnet such that tilting over of the flow flap from the first position to the second position actuates the switch.

A voltage regulation device includes: a plurality of taps; a first electrical contact configured to connect to one of the plurality of taps; a second electrical contact configured to connect to one of the plurality of taps; and a network electrically connected to the first electrical contact and to the second electrical contact. The network is configured to control a voltage differential between the first electrical contact and the second electrical contact or an amount of current that flows in the first electrical contact and the second electrical contact.

A bypass switching assembly includes a source terminal configured for connection to an electrical source; a load terminal configured for connection to a load; a switch including: a first electrically conductive element, a second electrically conductive element, and an electrically conductive bypass element; and an interlock assembly including: an insulator configured to rotate; and a locking assembly configured to interact with the insulator to prevent movement or permit movement of at least one of the first electrically conductive element and the second electrically conductive element.

A transformer test device (10) for testing a transformer (40) has connections (12) for releasably connecting the transformer test device (10) to the transformer (40). The transformer test device (10) has a source (13) for generating a test signal for testing the transformer (40). The transformer test device (10) has a controllable switching means (15) which is connected to the connections (12) during a transformer test for the purpose of short-circuiting at least one winding (42) of the transformer (40).

An on-load tap changer is provided having a plurality of modules, each of which is operable to change taps in a transformer winding. The tap changer includes a motor connected to rotate at least one shaft. The at least one shaft is connected to the tap change modules and is operable upon rotation to cause the tap change modules to each perform a sequence of operations that effectuate a tap change. A multi-turn absolute encoder is connected to the at least one shaft. A monitoring system is connected to the encoder and is operable to determine from the position of the at least one shaft where the tap change modules are in the sequence of operations.

The following steps are performed in order to test a tap changer of a transformer which tap changer is designed to change a transmission ratio of the transformer: generating a test signal which is supplied to a winding of the transformer and to the tap changer, repeatedly actuating the tap changer in order to change the transmission ratio with each actuation, determining a curve of an electrical measurement variable (I; I.sub.1; I.sub.2) of the transformer over time (t) for each actuation of the tap changer depending on the test signal filtering the curves in order to prevent at least one of the curves from being output outputting the filtered curves.

An on-load tap changer that includes an actuator configured to adjust a turn ratio of the transformer, and a processing unit configured to control the actuator and to communicate with a control device via a digital signal connection. The processing unit is further configured to receive a status detected by a sensor. A method of manufacturing the on-load tap changer is also disclosed. Embodiments according to the present disclosure provide a digitalized on-load tap changer that allows various statuses to be monitored or controlled, by which various advantages can be achieved. For example, the life of a contact of the transformer can be predicted. Other data can be used to determine whether it is safe to adjust the contact of the transformer. Moreover, the optical fibers between the on-load tap changer and an external device enable an isolated transmission of control and data signals that almost eliminates interferences.