Voltage and Disturbance Analyzers in Power Analysis
Power analysis is important to developers and users alike. On one hand, developers require analysis to eliminate undue interferences and disturbances in the functioning of equipment. On the other, users study power-line disturbances to safeguard equipment. Since the objectives of both are distinct, tests conducted by each also differ. While developers require load-related tests, users generally require source-related ones.
A power analyzer is a tool that allows monitoring of input voltage, power and current as also measurement of parameters like power factor, harmonic distortion, current crest factor, etc. Most electronic equipment uses switch mode electric supply (SMPS). An SPMS transfers power from the source and switches very quickly between fully on and fully off states to convert the voltage and current characteristics as required. Voltage regulation is a challenge when using such power supplies. Thus, to conduct a source-related test, the power analyzer measures time-stamps, blackouts, voltage fluctuations and spikes, noise and frequency and phase-shift changes.
Since the interference or disturbance cannot be pre-calculated, a range of anomalies should be recorded for purpose of analysis. Voltage recorders and disturbance analyzers record transient events and data that is logged in specific time periods and transferred to a PC to be graphed. A thorough analysis of the digital power meter readings and the previously recorded power-line data helps pinpoint the issue. Most disturbances caused by a switch-mode electric supply can be rectified using simple techniques. For instance, a dedicated electrical wiring circuit with provision for a voltage boost can correct abnormal average line voltages and simply adding a UPS system can counter blackouts.
While source-related tests are conducted to ensure fidelity and excellent functioning of the equipment, load-related tests are performed to determine design quality. A disturbance analyzer is used to measure steady-state or transient disturbances. The degree of current consumption is measured with a true-RMS-reading digital power meter with peak measurement capability. When used in conjunction with a current clamp, it works as a harmonics analyzer to measure phase relationships.Voltage recorders show that transient disturbances generally occur at start-up or due to sudden load changes. Slightly complex systems and operating cycles are required to measure transient disturbances.
Since non-linear loads are more prolific, the harmonic magnitudes allowed are limited as is the flicker or temporary voltage disturbance. The European Community (EC) has defined strict test procedures for measuring harmonic content, which have been accepted globally. IEC 1000-3-2 or EN61000-3-2 tests based on the original International Electrotechnical Commission (IEC) 555 Part 2 requirements are formalized. All electronic equipment to be sold in EC markets must pass these tests.