REACTIVE POWER-MEASURING DEVICE, REACTIVE ELECTRIC ENERGY-METERING DEVICE, POWER-MEASURING DEVICE, ELECTRIC ENERGY-METERING DEVICE, AND POWER FACTOR-MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To measure reactive power with a simple configuration by storing voltage and current data in the same phase for one cycle, cyclically multiplying current data at each sampling point by voltage data at a sampling point being shifted by 90 degrees, and calculating the reactive power from the average value. SOLUTION: One AC cycle is equally divided into eight portions for simultaneous sampling. Voltage and current data being inputted to a sample/hold part 13 of a sampling means 1 is converted into digital by an A/D conversion part 14, voltage data v1-v8 and current data i1-i8 for one cycle are stored in a memory means 2. A pseudo reactive power operation means 3 multiplies first current data i1 by voltage data v3 at a sampling point being delayed by 90 degrees, and multiplies the succeeding one cycle data from i2v4 to i6v8 successively. Voltage data v1 and v2 are circulated to i7 and i8 for multiplication, and the average value of the multiplication value is calculated. The processing control is made by a controller 15.