CET PMC-53A User Manual

CET Electric Technology
40
 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 * 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.
Predicted
Response
The Predicated Response shows the speed of the predicted
demand output. A value between 70 and 99 is recommended
for a reasonably fast response. Specify a higher value for
higher sensitivity.
70 to 99
Default=70
Table 4-4 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-53A provides the following PQ parameters:
4.3.2.1 Harmonics
The PMC-53A provides harmonic analysis for THD, TOHD, TEHD and individual harmonics up to the 31
st
order. All harmonic parameters are available on the Front Panel and through communications. In
addition, the PMC-53A also provides TDD, K-factor and Crest-factor measurements for Current.
4.3.2.2 TDD
Total Demand Distortion (TDD) is defined as the ratio of the RMS (Root Mean Square) of the Harmonic
Current to the RMS of the Rated or Maximum Fundamental Current Demand.
TDD of Current is calculated by the formula below:
where
I
L
= Maximum Fundamental Current Demand
h = Harmonic Order (1, 2, 3, 4, etc.)
I
h
= RMS Load Current at the n
th
Harmonic
4.3.2.3 K-Factor
K-Factor is defined as the weighted sum of the Harmonic Load Current according to their effects on
transformer heating, as derived from ANSI/IEEE C57.110. A K-Factor of 1.0 indicates a linear load (no

CET PMC-53A Specifications

General

Brand	CET
Model	PMC-53A
Category	Measuring Instruments
Language	English