Half Division Two-Dimensional Method for Accurate Measurement of Sinusoidal or Periodic Electrical Quantities Parameters

The article proposes several versions of a half division two-dimensional method, which is the basis of a fundamentally new approach for constructing measuring instruments for sinusoidal or periodic electrical quantities. These measuring instruments are used in the diagnostics of electric power facilities. The most general version, called the midpoint method, is considered. The proposed midpoint method allows measuring much smaller (of the order of hundreds of microamperes) alternating currents or voltages comparing to the widespread methods, especially when the amplitude of the measured signal changes in a very wide range (by 1–2 orders of magnitude). It is shown that using the midpoint method it is possible to suppress sinusoidal or periodic interference in the measuring path, in particular, to measure a small alternating current when the sinusoidal or periodic interference is 1–2 orders of magnitude higher than the useful signal. Based on the results of comparative tests, it was found that a current measuring device implementing the midpoint method is an order of magnitude more sensitive than the currently used high-precision measuring instruments.