| 摘要 |
<p>05 ME 86 PEAK DETECTION AND ELECTRONIC COMPENSATION OF D.C. SATURATION MAGNETIZATION IN CURRENT TRANSFORMERS USED IN WATT HOUR METER INSTALLATIONS A watt hour meter installation is described which is of the type including an input transformer having an input winding for connection to an alternating current power supply line, an output winding for connection to a watt hour meter for measuring alternating current power being consumed and a core on which the input and output windings are wound. The core is of the type which is susceptible to DC magnetization by a DC component superimposed on the alternating current being measured. In order to overcome the effect of the DC component on the magnetization characteristics of the input transformer, automatic compensation circuitry is provided which includes a sensor coupled to sense the current flowing through the input winding and for deriving a sensed output signal proportional to the sensed current and which includes both AC and DC components of the input current. A sensed signal processing circuit is provided in the form of positive and negative peak voltage detecting and holding circuits together with a summation circuit and voltage to current converter for deriving from the sensed signal a feedback signal which is proportional only to the DC component of the current flowing in the input winding. This feedback signal is supplied through a compensating winding wound on the input transformer core in a direction to automatically cancel out the effects of the superimposed DC component on the saturation characteristics of the input transformer.</p> |
