Recording and evaluation of measurement data

Disturbances in the energy supply can lead to production or operating equipment failures. Often a reaction is only taken when high financial damage has been caused. However, many of these incidents could be avoided if the signs were detected in time through continuous monitoring of the situation.

Power quality monitoring provides both a statistical evaluation that allows comparison with standards (e.g. EN 50160) or supply contracts, and records of network events (e.g. voltage dips) to analyse their causes and consequences.

Event recording

Principle

All voltages at the PCC or IPC are monitored for faults such as break-in, interruption or excessive supply. These faults are registered as events. There is no statistical evaluation as the number of permissible events is not limited. Each event record contains for a configurable duration and for all voltages and currents the waveform as well as the course of the RMS half-period values.

Benefits of event recording

By evaluating an incident recording, the cause of the malfunction can be determined and, in the best case, a correlation with detected events (such as failure of control systems or equipment) can be established. From this, suitable remedial measures can be derived and their effectiveness checked.

Statistical analysis

Principle

All relevant parameters of the supply voltage at the PCC are monitored, statistically averaged and compared with preset values. This can either prove conformity or draw attention to potential problems. The currents are also monitored for level, harmonic content and unbalance. However, as no limit values exist, these results are not part of the statistical analysis.

Benefits of statistical analysis

Verification of compliance with standards (e.g. EN 50160) or contracts between energy supplier and energy consumers. By observing the change in the results, a deterioration in the network quality can be detected at an early stage and reasons can be sought. The effectiveness of the measures introduced can be checked immediately.

Power Quality Evaluations




Classification by ITIC curve





Evaluation according to

  • IEC 61000-2-2 (NS)
  • IEC 61000-2-4 (Industry)
  • IEC 61000-2-12 (MS)
  • EN 50160
  • GB/T
  • IEEE519
  • Country specific
  • Application specific

Conclusion

In principle, it is important to understand that there are two different methods for assessing network quality. One is based on a conformity assessment using statistics and the other records actual disturbances (events) using disturbance recorders and a time stamp.