Operation Manual

MI 2092 Power Harmonics Analyser Section VI Theory of operation

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can be estimated with experience. It depends on the quality of voltage supply

and on the user defined limits for detection of anomalies. Selection of

excessively narrow limits, or a wrong nominal voltage reference, can produce

large numbers of recorded events and reducing memory capacity.

Example 1:

The Instrument will be set to log for 7 days.

The requirement is to monitor both voltage and current changes, and harmonic

distortion, with as much detail as possible.

For optimum memory usage, just 12 channels should be set for periodic analysis.

, U

, I

, thd

With this setting, the Instrument can save 24,771 records (values for 24,771 IPs).

Increasing number of channels and/or enabling Statistical Analysis would decrease

number of saved IPs.

max

= (2032) * 1024 / (12 + 12 * 6) = > 24,771

(Record Length = 12 + 12 * 6 = 84 bytes)

Thus, over a week (604,800 seconds) instrument can save a record every

30 seconds (an IP interval of 30 seconds).

604,800 seconds / 24771 = 24.4 seconds Set IP = 30 seconds

Thus, monitoring the above 12 parameters with an IP of 30 seconds will produce

20,160 records per week in memory. This will leave the following memory free:

FREE Memory = Memory Capacity - Memory Used

2032 * 1024 - 20,160 * 84 bytes

387,328 bytes.

This ‘FREE Memory’ is enough for recording 2361 Voltage Anomalies. Adding a

further channel to the recording (e.g. frequency) would leave the following memory free:

FREE Memory = Memory Capacity - Memory Used

2032*1024 - 20,160 * (84 + 12)

145,408 bytes. (Sufficient for 886 Voltage Anomalies)