CET PMC-340 User Manual

CET Inc.
25
Self-Read Time
The Self-Read Time allows the user to specify the time and
day of the month for the Peak Demand Self-Read operation.
The Self-Read Time supports three options:
 A zero value means that the Self-Read will take place at
00:00 of the first day of each month.
 A non-zero value means that the Self-Read will take place
at a specific time and day based on the formula: Self-Read
Time = Day x 100 + Hour where 0 ≤ Hour ≤ 23 and 1 ≤ Day
≤ 28. For example, the value 1512 means that the Self-
Read will take place at 12:00pm on the 15th day of each
month.
 A 0xFFFF value will disable the Self-Read operation and
replace it with manual operation. A manual reset will
cause the Max. Demand of This Month to be transferred
to the Max. Demand of Last Month and then reset. The
terms This Month and Last Month will become Since Last
Reset and Before Last Reset.
Default=0xFFFF
Table 4-5 Demand Setup
4.3 Power Quality
4.3.1 Phase Angles
Phase analysis is used to identify the angle relationship between 3-phase Voltages and Currents.
For WYE connected systems, the per phase difference of the Current and Voltage angles should
correspond to the per phase PF. For example, if the PF is 0.5 Lag and the Voltage phase angles are
0.0°, 240.0° and 120.0°, the Current phase angles should have the values of -60.0°, 180.0° and 60.0°.
4.3.2 Power Quality Parameters
The PMC-340 provides the following PQ parameters:
4.3.2.1 Harmonics
The PMC-340 provides THD, TOHD, TEHD and individual harmonics up to the 31
st
order. All harmonic
parameters are available through communication while THDs are available on the front panel display.
In addition, the PMC-340 also provides TDD, K-factor and Crest-factor measurements for Current,
which are only available through communication.
4.3.2.2 TDD
Total Demand Distortion (TDD) is defined as the ratio of the root mean square (RMS) of the harmonic
current to the root mean square value of the rated or maximum demand fundamental current,
expressed as a percentage.
TDD of the Current I is calculated by the formula below:
where
I
L
= maximum demand of fundamental current
h = harmonic order
I
h
= rms load current at the harmonic order h
4.3.2.3 K-Factor

CET PMC-340 Specifications

General

Brand	CET
Model	PMC-340
Category	Measuring Instruments
Language	English