An integrated circuit includes a first and a second conductive path over a substrate, a coil structure over the substrate, a voltage sensing circuit electrically coupled with the coil structure, and a ferromagnetic structure including an open portion. The first conductive path is configured to carry a first time-varying current and to generate a first time-varying magnetic field. The second conductive path is configured to carry a second time-varying current and to generate a second time-varying magnetic field. The first conductive path and the second conductive path extend through the open portion of the ferromagnetic structure. The first conductive path includes a first conductive line below the ferromagnetic structure, a second conductive line above the ferromagnetic structure, and a first via plug coplanar with the ferromagnetic structure, the first via plug electrically coupling the first conductive line and the second conductive line.

An integrated circuit includes a first and a second conductive path over a substrate, a coil structure over the substrate, a voltage sensing circuit electrically coupled with the coil structure, and a ferromagnetic structure including an open portion. The first conductive path is configured to carry a first time-varying current and to generate a first time-varying magnetic field. The second conductive path is configured to carry a second time-varying current and to generate a second time-varying magnetic field. The first conductive path and the second conductive path extend through the open portion of the ferromagnetic structure. The first conductive path includes a first conductive line below the ferromagnetic structure, a second conductive line above the ferromagnetic structure, and a first via plug coplanar with the ferromagnetic structure, the first via plug electrically coupling the first conductive line and the second conductive line.

A current transformer (CT) for the purpose of, for example, current measurement, that uses a power line as a first coil and a second coil for measurement purposes, is further equipped with a third coil. Circuitry connected to the third coil is adapted to measure a signal therefrom. The measured signal from the third coil is compared to a signal measured from the second coil and based on the results, internal CT parameters are determined allowing calibration of actual results to expected results thereby providing an improved accuracy. This is especially desirable when using the CT for measurement of the like of current or phase of the primary coil when measurements are adjusted using the newly determined calibration parameters.

A current transformer (CT) for the purpose of, for example, current measurement, that uses a power line as a first coil and a second coil for measurement purposes, is further equipped with a third coil. Circuitry connected to the third coil is adapted to measure a signal therefrom. The measured signal from the third coil is compared to a signal measured from the second coil and based on the results, internal CT parameters are determined allowing calibration of actual results to expected results thereby providing an improved accuracy. This is especially desirable when using the CT for measurement of the like of current or phase of the primary coil when measurements are adjusted using the newly determined calibration parameters.

A high voltage (HV) apparatus insulated with an insulating gel includes at least two electrically conductive elements, such as a head transformer cover, a head housing base, a core casing, a primary conductor, bottom external housing, a bottom support flange, and/or a core. At least one of the electrically conductive elements has a coating made of solid insulating material separating the surface of the conductive element from the insulating gel and adapted for limiting electron emission from the conductive elements into the insulating gel.

A high voltage (HV) apparatus insulated with an insulating gel includes at least two electrically conductive elements, such as a head transformer cover, a head housing base, a core casing, a primary conductor, bottom external housing, a bottom support flange, and/or a core. At least one of the electrically conductive elements has a coating made of solid insulating material separating the surface of the conductive element from the insulating gel and adapted for limiting electron emission from the conductive elements into the insulating gel.

An apparatus and a tool for installation of a measurement coil. The apparatus includes a tool and a holder. The tool includes a first portion and a second portion at least partially surrounding the first portion. The first portion is configured to receive a conductor and the second portion is configured to hold a measurement coil. The holder is configured to be detachably attached to the tool, wherein the holder is to be employed to install the tool holding the measurement coil onto a conductor. The first portion is configured to snap fit onto the conductor during installation, and the measurement coil at least partially surrounds the conductor when installed.

An apparatus and a tool for installation of a measurement coil. The apparatus includes a tool and a holder. The tool includes a first portion and a second portion at least partially surrounding the first portion. The first portion is configured to receive a conductor and the second portion is configured to hold a measurement coil. The holder is configured to be detachably attached to the tool, wherein the holder is to be employed to install the tool holding the measurement coil onto a conductor. The first portion is configured to snap fit onto the conductor during installation, and the measurement coil at least partially surrounds the conductor when installed.

A current transformer includes a first housing including a first handle portion and a first distal portion, a second housing including a second handle portion and a second distal portion, a first core having a first proximal core end and a first distal core end the first core mounted in rotational contact within the first distal portion, and a second core having a second proximal core end and a second distal core end, the second core mounted in rotational contact within the second distal portion, wherein the first housing is rotationally coupled to the second housing about a fulcrum point.

A current transformer (CT) for the purpose of, for example, current measurement, that uses a power line as a first coil and a second coil for measurement purposes, is further equipped with a third coil. Circuitry connected to the third coil is adapted to inject a known reference signal to the third coil of the CT. The injected reference signal, i.e., current, generates signals in the first and second coils of the CT. The signal generated in the second coil is compared using circuitry attached thereto to the reference signal. Based on the results, and the difference between the expected results and the actual results, updated calibration parameters are determined. These provide improved accuracy when using the CT, for example for measurement of the like of current or phase of the primary coil when measurements are adjusted using the newly determined calibration parameters.