POWER METER

For the operation of a self-testing meter the active power W1 on the load and the test active power Wt on the first (R1) or second (R2) voltage divider inside the voltage sensor (1) are measured. For measuring active power W1 on the load, the control output signal of the digital signal processor (8) in their first half-period T/2 connects the controlled switches (s1) and (s3), while in the second half of the period T/2 the controlled switches (s4) and (s2) are connected, whereas the specified control switches link the outputs of both sensors (1, 2) between themselves and mass. For measuring the test active power Wt on the resistors of the specified voltage dividers the digital signal processor (8) switches the polarity of test signals simultaneously with the specified switching of the four controlled switches (s1, s2, s3, s4). The testing of the power meter suggested by this invention is performed automatically at the measurement site and the result can be checked during any reading of the meter or any time by using remote reading. Za izvajanje samotestiranja števca se merita električno delo W1 na bremenu in testno električno delo Wt na prvem in drugem uporu (R1) oziroma (R2) delilnika napetosti v senzorju (1) napetosti. Za merjenje električnega dela W1 na bremenu krmilni izhodni signali digitalnega signalnega procesorja (8) v njihovi prvi polperiodi T/2 sklenejo krmiljeni stikali (s1) in (s3), v drugi polperiodi T/2 pa sklenejo krmiljeni stikali (s2) in (s4), pri čemer omenjena krmiljena stikala povezujejo izhode obeh senzorjev (1, 2) med seboj in z maso. Za merjenje testnega električnega dela Wt na uporih omenjenega delilnika napetosti digitalni signalni procesor (8) preklaplja polariteto testnih signalov sinhrono z omenjenim preklapljanjem štirih krmiljenih stikal (s1, s2, s3, s4). Preverjanje z izumom predlaganega števca električne energije poteka samodejno na merilnem mestu in se ugotovi rezultat ob vsakokratnem odčitavanju stanja števca ali daljinsko kadarkoli.ŕ