Systems and methods testing a power protection relay include a merging unit to receive signals from an electric power delivery system. The merging unit includes a test signal input to receive test signals from a testing device, a relay output to output at least one of the test signals to a power protection relay, a distribution output to output at least another of the test signals to one or more additional merging units, and a switch subsystem to route the test signal to the relay output or the distribution output.

Systems and methods testing a power protection relay include a merging unit to receive signals from an electric power delivery system. The merging unit includes a test signal input to receive test signals from a testing device, a relay output to output at least one of the test signals to a power protection relay, a distribution output to output at least another of the test signals to one or more additional merging units, and a switch subsystem to route the test signal to the relay output or the distribution output.

A monitoring system includes an array of optical sensors disposed within a transformer tank. Each optical sensor is configured to have an optical output that changes in response to a temperature within the transformer tank. An analyzer is coupled to the array of optical sensors. The analyzer is configured to determine a sensed temperature distribution based on the sensed temperature. The sensed temperature distribution is compared to an expected distribution. Exterior contamination of the transformer tank is detected based on the comparison.

The present disclosure relates to a calibration unit for a vector network analyzer (VNA). The calibration unit comprises a calibration circuit which is configured to provide the calibration standards open, short and match; and an isolation circuit. The calibration circuit comprises a first port which is arranged for being connected to a port of the VNA, a second port which is arranged for being connected to a device-under-test (DUT), and a third port which is connected to a first port of the isolation circuit; and the isolation circuit comprises a second port which is arranged for being connected to one or more further calibration units.

The present disclosure relates to a calibration unit for a vector network analyzer (VNA). The calibration unit comprises a calibration circuit which is configured to provide the calibration standards open, short and match; and an isolation circuit. The calibration circuit comprises a first port which is arranged for being connected to a port of the VNA, a second port which is arranged for being connected to a device-under-test (DUT), and a third port which is connected to a first port of the isolation circuit; and the isolation circuit comprises a second port which is arranged for being connected to one or more further calibration units.

The disclosure relates to the field of measurement and calibration of capacitance, especially the instrument of transferring capacitance. A wide range capacitor standard box comprises a chassis, 36 physical capacitors, and 4 changeover switches. Output ports are on the front panel of the chassis. 4 dial-switches select the output capacitance in values of 1, 2, 5 times of single-unit capacitance. The changeover switch has input terminals that connect to two electrodes of the physical capacitors, and output terminals that connect to the output ports. Comparing to decade capacitor standard boxes, the present box realizes capacitance outputs from 1 pF.sup.500 mF in values of 1, 2, 5 times of single-unit capacitance. The present box significantly extends the measurement range of capacitance, and makes the capacitor standard box smaller and lighter. By introducing a compensation function for open and short circuits, it is convenient and suitable for precision measurement.

The disclosure relates to the field of measurement and calibration of capacitance, especially the instrument of transferring capacitance. A wide range capacitor standard box comprises a chassis, 36 physical capacitors, and 4 changeover switches. Output ports are on the front panel of the chassis. 4 dial-switches select the output capacitance in values of 1, 2, 5 times of single-unit capacitance. The changeover switch has input terminals that connect to two electrodes of the physical capacitors, and output terminals that connect to the output ports. Comparing to decade capacitor standard boxes, the present box realizes capacitance outputs from 1 pF.sup.500 mF in values of 1, 2, 5 times of single-unit capacitance. The present box significantly extends the measurement range of capacitance, and makes the capacitor standard box smaller and lighter. By introducing a compensation function for open and short circuits, it is convenient and suitable for precision measurement.

The invention disclosed a high precision decade capacitor standard box. It comprises 6 sets of physical capacitors, 6 changeover switches, and output ports. Each set of physical capacitors include 4 physical capacitors, at least one capacitor has single-unit capacitance. The changeover switch implements the decade encoding of all the combinations of 4 physical capacitors. The changeover switch has input terminals that connect to two electrodes of physical capacitors, and output terminals that connect to the output ports of capacitor standard box to provide the selected capacitance. The capacitance values can be selected any integer from 0 to 10 times of single-unit capacitance. The decade encoding of all the combinations of 4 capacitors can reduce the number of required capacitors and wires for connecting capacitors. The open and short compensation are adopted in this decade capacitor standard, which minimizes error, improve accuracy, and is convenient for measurement, transport, and field application.

The invention disclosed a high precision decade capacitor standard box. It comprises 6 sets of physical capacitors, 6 changeover switches, and output ports. Each set of physical capacitors include 4 physical capacitors, at least one capacitor has single-unit capacitance. The changeover switch implements the decade encoding of all the combinations of 4 physical capacitors. The changeover switch has input terminals that connect to two electrodes of physical capacitors, and output terminals that connect to the output ports of capacitor standard box to provide the selected capacitance. The capacitance values can be selected any integer from 0 to 10 times of single-unit capacitance. The decade encoding of all the combinations of 4 capacitors can reduce the number of required capacitors and wires for connecting capacitors. The open and short compensation are adopted in this decade capacitor standard, which minimizes error, improve accuracy, and is convenient for measurement, transport, and field application.

Various embodiments of the present technology comprise a method and apparatus for determining a resistance value of a resistor in a battery system. In various embodiments, the apparatus comprises a sense resistor connected to a current sensor. The apparatus may be configured to compute a voltage-based RSOC value and a current-based RSOC value and extract a capacity value from each. Over time, the capacity values will diverge and the difference can be used to compute an actual value of the sense resistor.