AC-DC difference characteristics of high-voltage thermal converters

Abstract

This paper describes a study of high-voltage thermal converters (HVTC's) at voltages above 100 V at frequencies up to 100 kHz. Techniques for the construction of HVTC's are described, and the effects of aging and dielectric loss on the resistor, changes in the timing sequence of ac-dc difference tests, relay dead-times, warmup times, and voltage level dependence are given.

Calibration Process Quantity Reduction of the Thermal Voltage Converter Standard using a Three-stage Build-up and Build-down Method

“…The sources of the thermal conversion error were serial inductance from the measurement cable (LLine, reach ≤ 1 ppm); shunt admittance from the parasitic capacitance between the TE input terminals (Cinput, several ppm at 1 MHz); total skin effect from the heater resistance (RH1 and RH2 leads, RTC1 and RTC2 bead resistance, Rtee-connector, and Rhousing, tens of ppm at 1 MHz); distributed capacitance at the bead (extremely small); and bead admittance where, at frequencies up to 1 MHz, the capacitance was at the pF or nF level and resistance was greater than 100 MΩ where in this case was ≅0.5 GΩ. The thermal conversion error could also be influenced by thermoelectric characteristics (Huang et al, 1995). The thermal conversion error was extremely small (Halawa & Al-Rashid, 2010) and could be omitted using a fast-reversal DC (FRDC) technique.…”

A new binary inductive divider comparator system for measuring high-voltage thermal converters

“…This procedure determines the departure from the nominal ratio of the DVMs. Neglecting small second-order quantities, the relationship between the ac-dc differences of the higher voltage converter, and the lower voltage converter, , may be given in the form (1) In (1), is the departure of the ac from nominal ratio as determined by the BIVD, satisfying the equation where is the average voltage supplied by the high-voltage ac source, as determined by the high-voltage DVM and is the average voltage supplied by the low-voltage ac source, as…”

“…H IGH-VOLTAGE thermal converters (HVTCs) are used as standards of ac-dc difference and for the measurement and calibration of ac voltage up to 1000 V and 100 kHz [1]. A build-up or scaling procedure is generally employed to determine the ac-dc differences of these devices.…”

CCEM-K9 comparison of AC–DC high voltage standards

“…A regional key comparison, with the same travelling standards, designated EUROMET 557, started in parallel. At the same time, works performed in number of NMIs greatly improved performances of high voltage AC-DC transfer measurements [4][5][6][7][8].…”