Smart three phase split electricity energy meter

1 Overview
DTSY1277-STS is an active energy-metering instrument, using digital media as the data exchange medium. User will load the pre-purchased credit, with settlement in terms of kWh. This meter is equipped with a digital key pad interface, which is used for active energy metering & prepayment controlling. Besides the meter also has Infrared communication and other auxiliaries.

Normative references:
l IEC62052-11 Electricity metering equipment(AC)-General requirements, tests and test conditionsPart11:Metering equipment
l IEC62053-21 Electricity metering equipment(AC)-Particular requirements-Part21:Static meters for active energy(classes 1 and 2)
l IEC62055-31 Electricity metering -Payment systems-Part 31:Particular requirements static payment meters for active energy(class 1 and 2)
l IEC62055-41 Electricity metering-Payment systems-Part 41:Standard transfer specification (STS)- Application layer protocol for one - way token carrier systems

l IEC62055-51 Electricity metering-Payment systems-Part 51:Standard transfer specification (STS)-Physical layer protocol for one-way numeric and magnetic card token carriersl

2 Solution
The solution is consist of MCU and CIU. MCU contains Management and Controlling Unit, Measuring chip, load switch, memory circuit, Infrared communication circuit ,power-supply circuit, LED indicator. CIU contains input unit (keypad ), alarm buzzer and LCD display Unit etc.Current sampling adopts with manganin shunt. Voltage sampling adopts resistive divider network. The calibration of meters is completed through software directly.

3 Technical Parameters
3.1 Model Specification
Type:  DTSY1277-STS
Class:  1.0
Rated Voltage(Un):  3*240V
Frequency:  50Hz
Rated Current (Ib) :  10A
Max Current (Imax):  100A
Active Pulse Constant:1000imp/KWh
Reactive Pulse Constant:1000imp/KWh
Starting Current :  0.2%Ib 10mA
Current range for meter measuring:  20mA~100A
Frequent current specification :  10(100)A
Operating Voltage Range:  0.60Un~1.2Un
Communication types: Optical Port, RS 485/MBUS/PLC/GPRS

4 Metering Function
DTSY1277-STS is three phase four wire prepayment meter, can measure forward, reverse active and reactive energy can be accumulated, stored. Measure each phase active energy; store last 12 days data; calculate the remaining credit; measuring instantaneous output energy etc.

5 Pre-payment Function
DTSY1277-STS three-phase prepayment meter can choose pre-payment and post-payment style. When the meter chooses pre-payment type, this means the user needs to purchase the energy before consumption. The user need provide personal electricity account information and purchase a token of 20 numbers. Then input the token to the meter ,and generate relevant credit. The credit will decrease while user uses electricity. When the remaining credit is low, the meter will remind the user. When the remaining credit is zero,the meter will disconnect the power supply through controlling relay switch.

5.1 Power purchase  
On exhaustion of remaining credit, the user can go to any PHED outlet to purchase credit (Token) The seller will provide a 20 digital token by:
(1) The consumer goes to PHED sales business hall.
(2) Provide to the cashier the ID number of the meter.
(3) Tell the cashier you want to buy electricity and pay.
(4) On the receipt, you get a printed token (20 digit code).

5.2 Charge
User enters the sequence of 20 digital numbers in the meter by keyboard, After key authentication by energy meter, the meter accepts the purchase of token for power, and adjust the remaining capacity and the cumulative purchase of token for power, and the remaining capacity value is stored in the meter memory. and displays the installed electric power.
Three-phase Keypad Prepayment Energy Meter Purchase of electricity token input meter:
(1) In the meter by keypad, enter the 20 digital token.
(2) The confirmation number on the LCD.
(3) If the token is entered incorrectly, please use the keypad's "back button" to delete.
(4) All 20 digital input, press the Enter key to accept token.
(5) If the token input is correct, CIU will display the charging value for 2 seconds, then display the total credit after charging.    
(6) If the token is entered incorrectly, the LCD will display "".

5.3 Overload Control:
If the current exceed 72A, the internal relay will be interrupted. CIU will display as "". The relay will be automatic closed after 30min.     

6 Display Function
6.1  LCD display
When the meter is power on, the LCD will display the full screen as follows, after several seconds the screen will display the normal information.

The means of the sign on the screen are:
1- credit level    2-reverse power   3-tamper indicator  4-power unit   
5-relay indicator  6-item number    7-number information
The data shows that: six integers and two decimal places. The power unit kWh; active power unit(kW).
Credit level can be decided by the utility. different level will generate different alarm information to remind user.

6.2 Data display of meter
The 8-number data will display power information, billing information, token queue and remaining information.
Total power consumption will display as six integers and two decimal places.
When typing in the 20-number token ,the screen will display the latest inputting number.

6.3 LED display
1- Credit: indicate the remaining credit is low  

2-Active Pulse:Blink one time when active energy consume 0.1KWh.

3-Reactive Pulse:Blink one time when reactive energy consume 0.1KWh.

4-Tamper:indicate the terminal cover is open