Availability Based
Tariff Meter
LARSEN & TOUBRO LIMITED
Features of ABT Meter
• The Meter measures Active/Reactive energy on 3
phase, 4 wire principle,
• Computes the active energy import /export from the
substation bus bars during each successive 15 minutes
block and stores it in its Memory.
• Integrates the reactive energy algebraically into two
separate registers,
A) One for the period for which the average RMS
voltage is 103% or higher (High VARh),
B) The other for the period for which the average
RMS voltage is below 97.0% or lower (Low
VARH).
Features of ABT Meter
• Average frequency for each successive 15-min
block, as a 2-digit code
Original Frequency = 49 + 0.02*2-digit code.
• Net Wh transmitted during each successive 15minute block, upto second decimal, with
plus/minus sign
• Cumulative Wh transmitted at each midnight, in
six digits including one decimal
• Cumulative VARh transmitted for voltage high
condition, at each midnight in six digits including
one decimal
Features of ABT Meter
• Cumulative VARh transmittal for voltage
low condition, at each midnight, in six digits
including one decimal
• Date and time blocks of failure of VT
supply on any phase, as a star (*) mark
• The meters shall store all the listed data in
their memories for a period of ten days
• Battery back-up for data viewing display.
Basic Technical Specifications
•
. Accuracy Class
: 0.2
• INTERFACE
: WITH RS485
• Reference Voltage(Vref)
: 110V.(P-P)
• Rated Current ( Ib)
• Operating Voltage
• Operating Current
: 5A or 1A.
:+20% to -30% of Vref.
: 0.2% to 200% of Ib
Display List
i) Meter Serial No
ii) Date (year month day)
iii) Time ( hour min. sec. )
iv) Cumulative Wh reading
v) Average frequency of the last block
vi) Net Wh transmitted in last block
vii) Average % voltage
viii) Reactive power (VAR)
ix) Voltage - high VARh register reading
x) Voltage - low VARh register reading
xi) Low battery indication
:NP5001A
:081112 d
:151030 t
:12345.6 C
:49.89 F
:28.75 E
:99.2 U
:106.5 r
:01234.5 H
:00123.4 L
Data Collecting
Device
LARSEN & TOUBRO LIMITED
DCD Main Window
(D) COLL. SELECTED DATA
(U) PC COMMUNICATION
(P) PROGRAMMING MODE
(O) MEMORY STATUS CHECK
(R) ACCURACY
Data Collecting Device
1. Press (D) for Collecting of Meter
Dada
2. Press (U) for damping the data from
DCD to PC
3. Press (P) for enter into Programming
Mode i.e only for time adjustment for 1
minute
4. Press (O) for Memory status check
Time adjustment through DCD
After connecting the Optical Port to
the meter and DCD following step to
be done for Time adjustment.
1. Press “P” in DCD to enter in
Programming mode.
2. Enter the Password: XMISSION
Time adjustment through DCD
3. Press Enter after typing the
“XMISSION” in DCD
4. Following Manu will come after pressing
enter in DCD :
(A) Advance
(R) Retard
(X) back to Manu
Time adjustment through DCD
5. i) Press “A” if the meter time is slow
ii) Press “R” if the meter time is fast
N.B :
i) Program/ time adjustment (only for 1
minute) can be done one in a week.
ii) Time taken to adjustment one min.
1 hrs. 30 min i.e. 6 Blocks
iii) Time adjustment can be done only on
power On conditions
Do’s & Don'ts with DCD
1. Don’t keep the DCD in Suspended
mode
2. To save the battery life switch off the
DCD properly
3. DCD battery should be charged at least
twice in a week
4. Charging time is 3 hours
RS485 Network
• Serial Port, Local Area Communication
– Two-wire, multidropping
– Uncomplicated hardware
– No distance limitation within a premises
Hardware Required
• We have used IEC 1107 protocol for RS 485 communication.
• Recommended hardware is mentioned below :
1. Twisted pair with foil shielding and a drain wire
Make : Belden ( Product Code 9841/8162/9501) cost Rs. 49,000 per
305m or equivalent local cable cost Rs. 2,000 per 100m.
Characteristic Impedance : 120 Ohms
Twist/Feet : 10
2. RS 485 to RS 232 Converter
Make : Moxa
Model No : Transio A53
3. PSTN Modem : Used for data transfer on PSTN Line from S/S to LDC
Make : Multitech 33.6 Kbps
Model No : MT2834ZDXB
The System
Meter
RS232
D+
Collection Point
RS232 to
RS485
Converter
D-