A circuit breaker system has a circuit breaker with a circuit breaker communication unit. A display unit contains a display housing, and the circuit breaker and the display unit are configured such that the display unit is latched to the circuit breaker. The circuit breaker and the display unit, in the latched state, are connected to one another by a plug connection, such that data of the circuit breaker are displayable on the display unit. A display holder is provided, containing a holder housing and a holder communication unit. The display holder is configured such that the display unit can be latched into the display holder, that the display holder and the display unit, in the latched state, are connected to one another by an electrical plug connection, and that the display holder is configured such that the data of the circuit breaker are displayed in the latched state.

A circuit breaker system has a circuit breaker with a circuit breaker communication unit. A display unit contains a display housing, and the circuit breaker and the display unit are configured such that the display unit is latched to the circuit breaker. The circuit breaker and the display unit, in the latched state, are connected to one another by a plug connection, such that data of the circuit breaker are displayable on the display unit. A display holder is provided, containing a holder housing and a holder communication unit. The display holder is configured such that the display unit can be latched into the display holder, that the display holder and the display unit, in the latched state, are connected to one another by an electrical plug connection, and that the display holder is configured such that the data of the circuit breaker are displayed in the latched state.

A method for detecting fault direction of a transmission line of an AC power system and a control system using the same. The method includes sampling current values and voltage values at one end of the transmission line for a series of time points; computing instantaneous voltage values at compensated point on the transmission line from the current value samples and the voltage value samples based on a time domain lumped parameter differential equation for the transmission line for the series of time points; recording the current value samples and the computed instantaneous voltage values at the compensated point; computing at least one voltage fault component each using the recorded computed instantaneous voltage values for at least the at least two of the series of time points; identifying the fault direction in consideration of the at least one computed voltage fault component and the at least one computed current fault component; and generating a fault direction signal indicating the identified fault direction. Where a fault directional element is designed using the voltage fault components at the compensated point, it will work well for the AC power system with strong power source.

The present disclosure relates to generating reference signals for distance and directional elements in power systems. For example, an intelligent electronic device (IED) may receive A-phase, B-phase, and C-phase electrical measurements of a power system. The IED may transform the A-phase, B-phase, and C-phase measurements to a d-component, a q-component, and a 0-component. The IED may include an adaptive notch filter that reduces or eliminates a double frequency component that may be present when step changes of frequency and/or amplitude occur and/or when the A-phase, B-phase, and C-phase measurements have different amplitudes. By reducing the double frequency component, the IED may generate a more accurate ω which may allow for more accurately tracking changes to the polarizing source. Further, the IED may separately add inertia to the estimated angular frequency used in generating a reference signal.

Systems and methods may be used to determine fault types and/or directions even during a loss of potential by receiving, at one or more processors, an indication of a pre-fault power flow direction for a power delivery system. The one or more processors then determine a fault direction during a fault for the power delivery system using current vector angles and the pre-fault power flow direction.

A system for protecting at least one electrochemical cell, comprising circuitry configured to disconnect the at least one electrochemical cell at a first threshold current magnitude based on a first current flow direction through at least one relay and at a second threshold current magnitude based on a second current flow direction through the at least one relay, wherein the first current flow direction is different from the second current flow direction. A method for electrochemical cell protection. A system comprising circuitry configured to disconnect at least one portion of a circuit at a first threshold current magnitude based on a first current flow direction through at least one relay and at a second threshold current magnitude based on a second current flow direction through the at least one relay. A method for protecting at least one portion of a circuit.

The present disclosure relates to generating reference signals for distance and directional elements in power systems. For example, an intelligent electronic device (IED) may receive A-phase, B-phase, and C-phase electrical measurements of a power system. The IED may transform the A-phase, B-phase, and C-phase measurements to a d-component, a q-component, and a 0-component. The IED may include an adaptive notch filter that reduces or eliminates a double frequency component that may be present when step changes of frequency and/or amplitude occur and/or when the A-phase, B-phase, and C-phase measurements have different amplitudes. By reducing the double frequency component, the IED may generate a more accurate which may allow for more accurately tracking changes to the polarizing source. Further, the IED may separately add inertia to the estimated angular frequency used in generating a reference signal.

A reverse current protection circuit for a switch circuit includes a reverse current control circuit and an enable/disable circuit coupled to the reverse current control circuit. The reverse current control circuit is coupled to an input terminal and an output terminal of the switch circuit, and disconnects the output terminal of the switch circuit from the input terminal of the switch circuit when an output voltage of the switch circuit is higher than a first predetermined voltage. The enable/disable circuit disables the reverse current control circuit for a first predetermined time period when the output voltage of the switch circuit becomes lower than the first predetermined voltage after being higher than the first predetermined voltage, and enables the reverse current control circuit after the first predetermined time period.

A method for locating phase faults in a microgrid in off-grid mode. The method includes obtaining a grid topology of the microgrid having at least two busbars and determining the position of all circuit breaker position of the grid topology. Further, acquiring measurement data which includes current magnitude and voltage magnitude. Monitoring the at least two busbars for a voltage dip in one of phase-to-phase or phase-to-neutral voltages. On detecting a voltage dip, determining a defect phase having a minimum phase-to-neutral voltage value. And for the defect phase performing busbar analysis and feeder analysis, using phase-directional information.

In one aspect, a solid-state circuit breaker (SSCB) is provided. The SSCB is configured to generate a first output representative of a current through a current path of the SSCB. An analog fault detection circuit is coupled with first output and is configured to assert a second output in response to the current exceeding a trip current level. At least one analog-to-digital converter (ADC) is configured to generate samples of the first output, where the at least one ADC has a di/dt detection bandwidth that is less than a di/dt detection bandwidth of the analog fault detection circuit. The SSCB is further configured to disable the current path through the SSCB in response to determining, asynchronously, that either the second output is being asserted by the analog fault detection circuit or the samples indicate that the current through the current path exceeds the trip current level.