A ground fault detection circuit can include a band-pass filter that can have a first node and a second node that can be coupled to an earth ground. The first node can be coupled to a local ground of an automatic test equipment (ATE) system for an electrical device that can be coupled via at least one wire to the ATE. The band-pass filter can be configured to pass and amplify a test current signal established at the first node in response to a coupling of one of a conductor of the at least one wire carrying the test current signal to the local ground, and a conductive element of the electrical device carrying the test current signal to the local ground. A fault alert signal can be provided to provide an indication of ground fault based on a comparison of the amplified test current signal.

A ground fault sensing circuit system includes a current transformer having a first winding and a second winding on opposite halves of the current transformer, outputting first and second signals, each winding coupled to a processor that determines information about respective currents in conductors monitored by the current transformer, based on a combination of the first and second signals. In another embodiment, the current transformer has a third winding wrapped continuously around both halves of the current transformer, overlapped with the first and second windings, the third winding outputting a third signal coupled to the processor, which determines information about respective currents in conductors monitored by the current transformer, based on a combination of the first, second, and third signals.

A ground fault sensing circuit system includes a current transformer having a first winding and a second winding on opposite halves of the current transformer, outputting first and second signals, each winding coupled to a processor that determines information about respective currents in conductors monitored by the current transformer, based on a combination of the first and second signals. In another embodiment, the current transformer has a third winding wrapped continuously around both halves of the current transformer, overlapped with the first and second windings, the third winding outputting a third signal coupled to the processor, which determines information about respective currents in conductors monitored by the current transformer, based on a combination of the first, second, and third signals.

A cable with a signal detection function includes an insulating core, a second insulating layer, and a signal detection layer. The signal detection layer is for transmitting signal data. The cable further includes a second insulating layer, and plural signal detection layers provided for transmitting signal data. The signal detection layer and the insulating cores are disposed inside the second insulating layer, and the signal detection layer is cladded with plural insulating cores. If the first insulating layer in the signal detection layer is damaged, the signal detection layer will be electrically connected to the conductor assembly. The cable with the signal detection function can detect the abnormality of the insulating core through the signal detection layer to facilitate maintaining and repair the cable.

A cable with a signal detection function includes an insulating core, a second insulating layer, and a signal detection layer. The signal detection layer is for transmitting signal data. The cable further includes a second insulating layer, and plural signal detection layers provided for transmitting signal data. The signal detection layer and the insulating cores are disposed inside the second insulating layer, and the signal detection layer is cladded with plural insulating cores. If the first insulating layer in the signal detection layer is damaged, the signal detection layer will be electrically connected to the conductor assembly. The cable with the signal detection function can detect the abnormality of the insulating core through the signal detection layer to facilitate maintaining and repair the cable.

Circuits integrated or integrable with a photovoltaic panel to provide built-in functionality to the photovoltaic panel including safety features such as arc detection and elimination, ground fault detection and elimination, reverse current protection, monitoring of the performance of the photovoltaic panel, transmission of the monitored parameters and theft prevention of the photovoltaic panel. The circuits may avoid power conversion, for instance DC/DC power conversion, may avoid performing maximum power tracking to include a minimum number of components and thereby increase overall reliability.

Circuits integrated or integrable with a photovoltaic panel to provide built-in functionality to the photovoltaic panel including safety features such as arc detection and elimination, ground fault detection and elimination, reverse current protection, monitoring of the performance of the photovoltaic panel, transmission of the monitored parameters and theft prevention of the photovoltaic panel. The circuits may avoid power conversion, for instance DC/DC power conversion, may avoid performing maximum power tracking to include a minimum number of components and thereby increase overall reliability.

A fault managed power system (FMPS) and method monitors and detects fault currents in PoE, PFC, and other cables that indicate likely human contact with cable conductors. The level of current detected through the human body combined with a fast response time limits the energy to prevent a person from experiencing ventricular fibrillation, resulting in a so-called touch-safe level. For overload and short-circuit fault protection, the system automatically and immediately removes power from the cables. This limits the amount of energy provided into the fault, thereby maintaining touch-safe operation and also preventing electrical fires and system component protection. The system/method can accomplish this even at voltage levels considerably higher than existing touch-safe standards, for example, Class 2 (below 50 Vac) power supplies. Such a system/method allows the amount of power in applications like PoE and PFC to be safely increased to levels much greater than the current maximum (100 W).

A fault managed power system (FMPS) and method monitors and detects fault currents in PoE, PFC, and other cables that indicate likely human contact with cable conductors. The level of current detected through the human body combined with a fast response time limits the energy to prevent a person from experiencing ventricular fibrillation, resulting in a so-called touch-safe level. For overload and short-circuit fault protection, the system automatically and immediately removes power from the cables. This limits the amount of energy provided into the fault, thereby maintaining touch-safe operation and also preventing electrical fires and system component protection. The system/method can accomplish this even at voltage levels considerably higher than existing touch-safe standards, for example, Class 2 (below 50 Vac) power supplies. Such a system/method allows the amount of power in applications like PoE and PFC to be safely increased to levels much greater than the current maximum (100 W).

A power cord includes multiple current-carrying wires covered by an outer insulating layer, each wire including a current-carrying conductor covered by an insulating layer. At least one wire further includes a shield layer covering the insulating layer and a metal conductor between the insulating layer and the shield layer. The shield layer is formed of a band wound around the metal conductor and insulating layer. The outward-facing surface of the band is insulating; the inward-facing surface has one or more conductive regions and one or more insulating regions. One insulating region is located along a longitudinal trailing edge of the band. Consecutive turns of the band partially overlap each other; the trailing edge of a subsequent turn is disposed over part of a previous turn. The structure ensures effective insulation of the metal conductor from other components. The power cord is used in a leakage current detection and interruption device.