Methods and devices for insulation monitoring of an ungrounded IT power supply system having at least two phase conductors includes determining an insulation resistance separately for each phase conductor using a separate response value. In one embodiment of the invention, relevant current and voltage distributions are calculated. In another embodiment, a change time window is set within which a second response value is activated. In yet another embodiment, an option of shutting down/continuing operation of the IT power supply system is offered.

Methods and devices for insulation monitoring of an ungrounded IT power supply system having at least two phase conductors includes determining an insulation resistance separately for each phase conductor using a separate response value. In one embodiment of the invention, relevant current and voltage distributions are calculated. In another embodiment, a change time window is set within which a second response value is activated. In yet another embodiment, an option of shutting down/continuing operation of the IT power supply system is offered.

Methods and devices for insulation monitoring of an ungrounded IT power supply system having at least two phase conductors includes determining an insulation resistance separately for each phase conductor using a separate response value. In one embodiment of the invention, relevant current and voltage distributions are calculated. In another embodiment, a change time window is set within which a second response value is activated. In yet another embodiment, an option of shutting down/continuing operation of the IT power supply system is offered.

Methods and devices for insulation monitoring of an ungrounded IT power supply system having at least two phase conductors includes determining an insulation resistance separately for each phase conductor using a separate response value. In one embodiment of the invention, relevant current and voltage distributions are calculated. In another embodiment, a change time window is set within which a second response value is activated. In yet another embodiment, an option of shutting down/continuing operation of the IT power supply system is offered.

An apparatus for determining a fault location distance or distance protection in a multi-phase power transmission medium, configured to; determine a set of line fault parameters based on a measurement of voltage and current at a point of said power transmission medium and a fault type, the line fault parameters determined at a plurality of sample times determine a derivative with respect to time of a line fault parameters representative of an inductive part of measured faulty phase current; determine a set of phasors using a Fourier transformation of the derivative and of the remaining line fault parameters at the plurality of sample times and use said set of phasors to determine a fault location distance or distance projection distance along the power transmission medium; wherein, the determination of the fault location distance or the distance protection distance is based on the line equation; ${\stackrel{.}{U}}_P={\stackrel{.}{U}}_F+\left[R_1{\stackrel{.}{I}}_{\mathrm{PR}}+\frac{X_1}{{}_0}{\stackrel{.}{I}}_{\mathrm{PX}}\right]D_F.$

A power supply protection circuit is a circuit that controls a protection switch provided on a power supply line connecting a direct current power supply and a load circuit. The power supply protection circuit includes: circuitry connected to the protection switch; and a controller that switches an operation state of the circuitry between a first state and a second state. The first state is an operation state in which driving of the protection switch is enabled when the protection switch is a first semiconductor switch having a control terminal connected to a semiconductor layer of a first conductivity type. The second state is an operation state in which driving of the protection switch is enabled when the protection switch is a second semiconductor switch having a control terminal connected to a semiconductor layer of a second conductivity type that is different from the semiconductor layer of a first conductivity type.

Systems, methods, and products are described herein for identifying deviations within a power system. Using time-synchronized measurement devices, a set of voltages and currents associated with a plurality of electrical components within the power system are continuously measured. For each electrical component of the plurality of electrical components, a representative set of parameters are recursively determined based on the measured set of voltages and currents. For each electrical component, an electrical characteristic value is determined based on the representative set of parameters. For each electrical component, a deviation of the electrical component is identified based on comparison of the determined electrical characteristic value with a reference value of the electrical characteristic of the electrical component or based on identifying the deviation by means of a filtered rate of change. An alert of the deviation is provided for further characterization of an abnormality in the power system.

An AC power supply system and a state monitoring circuit for the same, and a power consumption equipment are provided. The state monitoring circuit includes: a monitoring circuitry, configured to monitor current state information of the AC power supply system; and a control circuitry, coupled with the monitoring circuitry and configured to identify a current state of the AC power supply system based on the current state information monitored by the monitoring circuitry, and to determine whether to enable an AC power supply to deliver electrical energy to a power consumption equipment. Safety during an AC power supply process may be improved.

Systems, methods, and products are described herein for identifying deviations within a power system. Using time-synchronized measurement devices, a set of voltages and currents associated with a plurality of electrical components within the power system are continuously measured. For each electrical component of the plurality of electrical components, a representative set of parameters are recursively determined based on the measured set of voltages and currents. For each electrical component, an electrical characteristic value is determined based on the representative set of parameters. For each electrical component, a deviation of the electrical component is identified based on comparison of the determined electrical characteristic value with a reference value of the electrical characteristic of the electrical component or based on identifying the deviation by means of a filtered rate of change. An alert of the deviation is provided for further characterization of an abnormality in the power system.

A method and apparatus for suppressing the impact of a compensator on line distance protection is provided, wherein the method comprises: obtaining a first current of a line connected to a compensator or series converters in the compensator, and a first voltage of a bus connected to the compensator or the line connected to the compensator; exiting the series converters and series transformers if the first current is greater than a preset current threshold and a duration is greater than a first preset time threshold; exiting the series converters and the series transformers if the first voltage is less than or equal to a preset voltage threshold and duration is greater than a second preset time threshold set the output voltage of the series converters to zero, and if a second current of an element corresponding to the first current meets conditions which the first current needs to meet; and otherwise, canceling the setting of the output voltage of the series converters to zero and obtaining a first current if a second voltage of the line corresponding to the first voltage is greater than the preset voltage threshold and the duration is greater than a third preset time threshold.