How do power quality and energy measurement work?

From voltage and current to power and energy information

Voltage alone does not explain an electrical circuit's consumption. The measuring device evaluates voltage together with the circuit's load current. The relationship between phases and current behaviour relative to voltage are used to obtain quantities such as active, reactive and apparent power. Active power describes the current rate of energy transfer, while active energy is the accumulated amount over a period. Instantaneous power and the energy total on a meter therefore answer different questions.

In three-phase measurement, each current input must be matched to the correct phase voltage. The current transformer ratio and connection direction are also considered. The measurement chain includes voltage connections, the current sensor, device settings and communication information. A displayed value alone does not prove that the connections are correct under every condition.

The difference between power quality analysis and consumption recording

PEM353 provides harmonic and total harmonic distortion information alongside voltage, current, power and energy. This allows electrical conditions and consumption to be examined together. Threshold monitoring and recording capabilities depend on the variant; features such as neutral current measurement through a separate input are not identical across all PEM353 versions.

ALD1, ALE3 and AWD3 energy meter options emphasise consumption recording for energy management, while also providing voltage, current, power and cos φ data. Data can be transferred using Modbus RTU. Providing these values does not mean an energy meter also offers the PEM353's harmonic analysis capabilities. Single-phase, three-phase and current-transformer connection options are selected from the relevant model table. Certification and intended use must also be checked for the exact ordering variant.

How does CTB/KBR load current measurement differ?

For load current measurement, CTB/KBR converts the current in the monitored phase conductor into a secondary current suited to the measuring device input. CTB is an example of a closed-window transformer and KBR of a split-core transformer. Primary/secondary ratio, measuring range and required accuracy are selected together with the device. A family offering 1 A and 5 A secondary options does not mean each option suits every PEM input. The published PEM353 variant table specifies 5 A phase current inputs.

This differs from residual current measurement. In RCM, all live conductors of the monitored circuit, including the neutral where present, pass through a shared measuring window; PE does not. The evaluated quantity is the difference in the sum of currents, rather than the load current of one phase. A load current transformer therefore cannot be selected in place of an RCM sensor merely because they look physically similar.

From the measurement objective to a suitable Bender solution

First define the information required: a meter for total consumption, a suitable PEM solution for power and harmonic behaviour, or a compatible RCM measurement chain for residual current monitoring. Collecting values over communication does not change these devices' measuring tasks. As Bender's distributor in Türkiye, ADEO Teknik supports product selection and access to current technical documents.