Method for measuring balanced voltage components in a multi-phase system, and devices for carrying out the method

摘要

The invention relates to metrology. The method consists in generating the reference signals which, according to the invention, represent a system of two orthogonal sinusoidal signals, multiplying of their instantaneous values by the instantaneous values of the phase voltages and averaging the products obtained. After the averaging, the average values of the products are added to the corresponding weight factors for separating orthogonal components of symmetrical sequences, in accordance with which the parameters of the balanced components are evaluated. Devices for carrying out the method according to the invention are also proposed which are built up on the basis of digital computer technology. In the preferred variant of the embodiment, the device according to the invention contains a change-over switch (25), a voltage-code converter (27) and a computing unit (29), which are connected in series and are synchronised in their function by a control section (28). A frequency multiplier (26), which is also connected to one of the phases of the multi-phase system to be examined, is connected to the input of the control section (28). In this modification, the output signal of the computing unit (29) carries the information on the parameters of the balanced components of the said multi-phase system. The present invention is particularly well suited for use in measuring and information systems for measuring the quality characteristics of the electrical energy of a three-phase system. <IMAGE>