Strømmåling

Strømmåling, or current measurement, is the process of determining the flow of electric charge in a conductor or circuit. It is fundamental in electrical engineering for monitoring power consumption, protecting equipment, controlling systems, and validating measurements in laboratories and industry.

In most cases, current is measured by inserting a sensor in series with the circuit so the same current flows through the sensor as in the circuit. Direct insertion uses an ammeter or a low-value shunt resistor to generate a small voltage proportional to current. For larger currents or higher accuracy, devices provide electrical isolation and minimize circuit disturbance.

Common sensing technologies include shunt resistors, which produce a voltage drop; Hall effect sensors, which detect magnetic fields generated by current; current transformers for alternating currents in power systems; Rogowski coils for AC currents, which measure the derivative of current and require signal processing to obtain the actual value; and optical or other isolated sensors when galvanic isolation is required. Direct current measurement often relies on shunts or Hall sensors, while AC measurements frequently employ transformers or Rogowski coils.

Applications span electrical meters, switchboards, motor drives, battery management systems, power monitoring, and laboratory test benches. Performance depends on accuracy, bandwidth, and stability under temperature and magnetic influences.

Standards and calibration practices emphasize traceability to international units and repeatability of results. Measurement devices are subject to safety and isolation requirements, with design and testing aligned to relevant IEC and IEEE standards for instrumentation, metering, and current transformers.

Limitations include potential circuit disturbance, temperature drift, and susceptibility to magnetic interference. Proper selection of sensor type, range, and installation is essential for reliable strømmåling in a given application.