Electro Industries/GaugeTech Nexus 1250, Installation & Operation Manual

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Electro Industries/GaugeTech
Doc #: E107-6-07-121
7-3
7.3: Loss Compensation Percentages 7.3: Loss Compensation Percentages
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Loss compensation percentages are values that describe the percentage Watt and Var losses due to
Iron and Copper at the loss calibration point of the Nexus Monitor. Losses due to Iron manifest
themselves in changes to the measured voltage. Losses due to Copper manifest themselves in
changes to the measured current.
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Transformer characteristics are published in the documentation accompanying individual
transformers. Manufacturers determine the following characteristics when testing transformers for
proper operation:
•
Transformer Bank Rating (Self Cooled)
•
Test Phase Voltage (Low Side)
•
No Load Loss Watts
•
Load Loss Watts
•
% Exciting Current
•
% Impedance
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Meter characteristics specify the type of meter type, class, etc., as ordered by the customer. The
information is published in documentation accompanying individual meters. The different
characteristics are:
•
Voltage Transformer Ratio (VTR)
•
Current Transformer Ratio (CTR)
•
Meter Secondary Voltage (always 120V for Nexus Transformer Loss Compensation)
•
Meter Secondary Phase Current (always 5A for Nexus Transformer Loss Compensation)
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Derivation equations detail the calculation of Loss Compensation Percentages from the
Transformer and Meter characteristics. The following symbols represent Loss Compensation
Percentages:
•
%LWFE—Percent Loss of Watts due to Iron
•
%LWCU—Percent Loss of Watts due to Copper
•
%LVFE—Percent Loss of Vars due to Iron
•
%LVCU—Percent Loss of Vars due to Copper
Courtesy of NationalSwitchgear.com