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Every Power distribution system
requires reliable metering of various electrical parameters.
From the electricity user’s point of view, this is important
for saving of electrical energy, where-ever possible. For the
utility provider however, accurate & reliable metering is
vital if he is to use the distribution optimally. Not only
should every distribution transformer be loaded maximum, but
also operate at near unity power factor. The load imbalance on
the three phases should be within reasonable limits. Thus,
information like amount of loading imbalance, power factors at
different times of the day, peak loading hour etc. can be of
great help in planning distribution of power and also
implementing automatic switched capacitor systems to maintain
power factor near unity.
- Once having implemented a
switched capacitor scheme, the provider would also like to
know how the scheme is performing, the rating and health of
capacitors etc. This is where VARLOG™ comes in.
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- VARLOG™ is an electrical
parameter measurement instrument and logger which measures /
calculates and displays the following parameters :
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- 1. Three phase
voltages.
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- 2. Three phase
(load) currents.
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- 3. Frequency.
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- 4. Power Factor
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- 5. System KVA, KW
& KVAR
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- 6. Three phase
(capacitor) currents
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- 7. Capacitor KVAR
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- 8. Date & Time
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In addition to this, VARLOG™, also logs all these
parameters in it’s non-volatile memory, every four
minutes. There is no need for any manual intervention here.
Afterwards, any operator can download the recorded data on
an IBM compatible, using the serial link provided. This data
yields itself to further analysis like load current without
capacitors, Power factor without capacitors etc. and the
utility provider can actually calculate KVA saved and
quantify it in terms of currency.
Other Features:
- VARLOG™ not only monitors
load currents but also capacitor currents thus allowing
utility company to know whether capacitors are de-rated or
failed.
- VARLOG™ is meant for use in
three phase four wire L.T. electrical system. It uses the
three watt-meter method to calculate KVA, KW & KVAR.
- VARLOG™ is based on a
powerful 8-bit micro-controller operating at 16 MHz. The
controller receives voltage & current signals which are
fully isolated and performs high speed measurement and
calculations, typically finishing one complete measurement
cycle in less than a second.
- The unit displays all
parameters locally on a 16 x 1 STN LCD. The user-friendly
membrane keypad on the front makes programming the unit (for
C.T. ratios etc. ) very easy.
- VARLOG™ has a FIFO buffer
for logging data. If the buffer gets full, the oldest record
shifts out and the new data shifts in. Thus, when the data
is downloaded, the records of the last 100 hours or so will
be sent down by the VARLOG™ to the PC.
- VARLOG™ is thus a very
versatile and accurate information interface for both the
utility provider and end user.
SPECIAL FEATURE OF VARLOG™:
PROGRAMMABLE FEATURE: The VARLOG™ has basically five
programmable parameters : date, day of week, time, CT ratio for
load currents and CT ratio for capacitor currents. These have to
be programmed, in most cases, only once at the time of
commissioning a new unit. To differentiate between programming
operations and normal functioning of the unit, VARLOG™ has two
modes of operation: PROG mode and RUN mode. Whenever the unit is
powered ON it is in the RUN mode. It is in this mode that it
displays all the parameters one by one on the front LCD. To set
any of the above mentioned programmable values, the user has to
go into RUN mode, set/change the values and return to RUN mode.
SPECIAL FEATURE OF THE
SOFTWARE: CAPABILITY FOR IMPORTING TO MS-EXCEL: The
file created after filter is basically an ascii file. One can
directly view it using any ascii text editor and print it.
However, in order to do further calculations or maybe generate
graphs, it is best to use a spread-sheet package. Lotus does not
import ascii files. However, MS-EXCEL is a spread-sheet package
which easily imports ascii data. It is also very user friendly.
To read file into EXCEL, just run EXCEL from Windows and giving
read file option, select our filename as c:\procomm\jubilee.log.
The file will get opened in EXCEL.
- Technical
Specifications
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- Electrical System
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- 3 Phase, 4 Wire System
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- Voltage Connections
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- R.Y.B and Neutral
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- Current Connections
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- 3 CT secondaries (5
Amps) from system. One from each phase.
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- CT Ratios
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- CT ratios for system
current will be site Programmable
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- Operator Interface
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- Membrane Keypad (16
keys - 4X4 matrix) on the front of the unit, used
for programming various parameters like date, time
and CT ratios.
- Local Alphanumeric
display, 16 X 1 LCD
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- Displayed Parameter
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- Vr, Vy, Vb, Ir, Iy, Ib,
PF, Frequency, KVA, KW, KVAR, Day, Date and time.
Each Parameter is displayed for the duration of 6
secs.
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- Parameters Logged and
Transferred to PC
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- Vry, Vyb, Vbr, Ir, Iy,
Ib, PF, KVA, KW, un-compensated, KVAR, ILR, ILY, ILB.
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- Connectivity to PC
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- RS232C Link, 9 Pin D
Connector on the PC end. Communication parameters:
4800 baud, 7 databits, odd parity 1 stopbit.
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- Max Number of Records
Logged
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- 1200 records. After
that, when the new record comes in, oldest record is
pushed out and new record is added
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- Frequency of Logging
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- One record logged
every 4 minutes between 6 AM and Midnight. Between
midnight and 6 AM, one record every 6 minutes. This
is the default setting and is programmable.
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- Size
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- Panel Cutout: 138mm x
138mm
- Bezel: 144mm x 144mm
- Depth: 140 mm with
terminal (max)
- Weight: 4Kgs.
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- Additional Features
(Optional)
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- Logger can be modified
as per customer requirement like extending number of
records to log data for 30 days, logging of
Capacitor current etc., as additional features at
additional cost.
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