| 摘要 |
<p>The invention concerns a measurement wiring for measurement apparatuses intended for measurements of energy in a three-phase network, which measurement apparatuses comprise internally at least one, usually two or three identical power measurement mechanisms, whose output data are summed up in order to provide a result of measurement of energy. The measurement wiring (20) comprises pulse-width modulators (21,22,23), which form pulse-width modulated digital data (DL1, DL2, DL3) and negations ( DL1, DL2, DL3) of said digital data out of each momentary value of the phase voltage of the three-phase network, a pulse width-height multiplier (26), and a control logic (24), by whose means the controls (Q1A,Q1B,Q2A,Q2B, Q3A,Q3B) are chosen from said pulse-width modulated digital data (DL1, DL2, DL3) and from their negations ( DL1, DL2, DL3) for the pulse width-height multiplier (26). The secondary current (It) of the measurement transformer (31,32,33) of each phase current of the three-phase network is passed to the pulse width-height multiplier (26), the output (41,42,43) of said pulse width-height multiplier (26) being proportional to the energy quantity supposed to be measured at each particular time. <IMAGE></p> |
