Model: PM-2160-A
Doc. Ref. no. : m20Aom201
Issue no. 02
User’s Manual
Page 34 of 36
Energy Calculation
Below formula used for finding the Total Active Energy Import.
Total Active Energy = [Running Active Energy (Import) + (WH-I Ov.count * 400G)]
(Import)
Example
:
Let‟s WH-I Ov.count = 5, Active[Im] = 20.3268 GWh then
Actually measured Total Active Energy (Import) = [20.3268 G + (5 * 400G)]
= 2020.3268 GWh
Above calculation is same for other energy (Active Export, Reactive Import, Reactive
Export, and Apparent Energy) can be find out using respective Ov.count and running
energy.
Energy Overflow Time Calculation
When data type selected for modbus is FLOAT, Total apparent Energy will overflow from
400GVAhr then auto reset Apparent Energy, but when the ov.count of this energy (VA
Ov.count > 99) then meter will auto reset all energy parameter. This includes Active
import and export energy, Reactive Import and Export energy and apparent energy. Such
condition of overflow occurrence is depending on CT ratio and PT ratio.
Example
:
For 110V V rated, and 1 A I rated multifunction meter is set for 100A and 66KV line with
CT Ratio of 100 and PT Ratio of 600.
PT Primary = 66KV, PT Secondary = 110V Therefore select Vrated = 110V.
PTR
= 66KV/110V=600 select.
CT Primary=100A, CT Secondary=1A Therefore select Irated = 1A.
CTR
= 100A/1A=100 select in meter.
Energy consumed per hour will be 66kV X 100Amps = 6600KVAHr.
Time to overflow in Hr. = 400GVAhr / 6600KvaHr = 60606 Hr
Days = 60606 /24 = 2525 Days
Years = 2525 / 365 = 6.91 Years / Total of Three Phase.
But our Apparent Energy Overflow Count Range are 1 to 99, therefore
Total Time to overflow in Years = 6.91*99 = 684.09 Years / Total of Three Phase.
User has to manually reset
All Regs Rst,
when installing the meter first time.
As above for 100A and 66KV line, PT Primary = 66KV, PT Secondary = 110V Therefore
Vrated = 110V select. PTR = 66KV/110V=600 select.
CT Primary=100A, CT Secondary=1A Therefore Irated = 1A select. CTR = 100A/1A=100
select in meter.
Energy Resolution on Modbus
Resolution of the energy parameter on the Modbus when data is transmitted in LONG
format is 100VAhr/Whr/VARhr rather than 1VAhr/Whr/VARhr, which is possible when
FLOAT data type is used. Because of the limitation of the Long Data type and to avoid
frequent reset, Data is transmitted in with above-mentioned resolution.
Due to this resolution on display of the Meter will not be same as ON ModBus data, when
data is transmitted in LONG format. Multiplication factor given on master side is 0.0001.
Example
:
Lets say on modbus data transmitted is 20098798 then on the master side it will be
20098798 * 0.0001 = 2009.8798 MWhr/MVAhr/MVARhr.
Which
gives
the
resolution
of
the
0.1KWhr/KVAhr/KVARhr
as
described
above.
