Technical Specification-ABT Meter

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1 Scope

The Technical Specification shall cover the design, engineering, manufacture, assembly, inspection & testing at manufacturer’s works before supply and delivery at site / FOR destination of class 0.2s accuracy static HT tri vector availability based tariff meters. The offered meters shall be suitable for commercial/tariff metering for bulk, inter utility power flows as well open access consumer for ABT application.

The said meters will be installed on various EHV/HV lines as a self-contained device for measurement of average frequency and active energy for each successive 15 minute blocks as per relevant national/international standards. The meter shall be capable of other tariff applications like Time of Day (TOD) metering.

The offered metering system shall be projection type.

The meters shall be 3 phase 4 wire type suitable for connection to 3 phase 4 wire systems. The meter shall be capable to record and display Active, Reactive and Apparent energy and maximum demand(kW/kVA) for 3 phase 4 wire AC balanced/ unbalanced loads for a power factor range of zero (lagging), unity and zero (leading) for both export and import. In other words, the meter shall be capable of measuring and recording in all the four quadrants.

The meters shall have two test outputs (for Active and Reactive) in the form of blinking LED’s for testing the meters accuracy. Testing shall also be possible through optical port accessible from the front and can be monitored with Meter Reading Instrument having high-resolution display.

2 Applicable Standards

The offered meters shall conform to the following Indian/International Standards and all related Indian/International Standards, which are to be read with up to date and latest amendments/revisions thereof:

2.1 Electrical Standards

S. No. Standard No. Title 1 IS 14697-1999 With latest

amendment/s

AC static transformer operated Watt-hour and VAR-Watt-hour meters for class 0.2S,0.5S and 1.0S

2 CBIP Technical Report 304 with latest amendments

Specification for AC static electrical energy meters

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4 amendment/s energy class 0.2S and 0.5S.

4 IS-9000 With latest amendment/s

Basic environmental testing procedures for electronic and electrical items.

2.2 Mechanical Standards

S. No. Standard No. Title 1. IS:12063/IEC529 for degree of

protection of IP51 in normal Working Condition

Protection against ingress of dust, moisture and vermin.

2.3 Communication Standards

S. No. Standard No. Title 1. CBIP Tech Report No.111 with

Latest Amendments

For Common Meter Reading Instruments & Optical ports in Use 2. IEC:1107/IEC-62056-21 For Galvanically isolated optical ports.

3 General Meter/System Requirements

The 3phase 4wire Meter shall be projection type suitable to install with the secondary of CT/VT of Supply Network. This complies with an accuracy standard of 0.2S as per relevant standards.

3.1 Auxiliary Power Supply

The Meter shall have a provision to work on Auxiliary AC/DC supply and shall not burden the secondary of PT/VTs. In normal condition meter shall work on Auxiliary AC supply and in case of Auxiliary AC failure shall automatically change over to DC. Meter shall have clearly identifiable separate Auxiliary supplies with an appropriate connection diagram on the Name Plate.

S. No. Type of Supply (Auxiliary) Operating Range

1. AC supply 230 (+10% to -15%) Volt 2. DC Supply 110/ 220 (+10% to -15%) Volt

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3.2 Rated Electrical Parameter

The meter is rated for the following input conditions

S. No. Items Specified Operating Range Limit Operating Range 1. Voltage 3*110volts P-P, 3*63.5volts

P-N

(3phase, 4Wire)

+20% to -30% Vref

2. Current Suitable for -/5 or -/1Amp Imax = 120%Ib

Starting Current = 0.1%Ib 3. Frequency 50Hz ±5% (47.5 to 52.5)Hz 4. Power Factor Zero(lag)-Unity-Zero(Lead) As per relevant Standard 5. Power

Consumption

Voltage Circuit

The power consumption shall not be greater than 1.5watts & 10VA in reference operating conditions.

Current Circuit

It shall not be greater than 1VA in reference Operating Conditions.

As per relevant Standard

6. Accuracy 0.2S Accuracy shall be as per relevant Standard

The meters shall withstand the fluctuations arising during line faults. Specifically, 115% of rated VT secondary voltage applied continuously; 190% of rated VT secondary voltage applied for 3 seconds; 120% of rated CT secondary current applied continuously; or 20 times of maximum current applied for 0.5 seconds-- shall not cause any damage to or the mal -functioning of the meter.

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3.3 Climatic Conditions

The meter shall be suitable to work satisfactorily under the climatic conditions of temperature & humidity as defined in relevant standards as specified in Clause 2.0.

S.No. Particulars Conditions

1. Maximum ambient air temperature in shade 50⁰C 2. Minimum ambient air temperature in shade (-)5⁰C 3. Maximum relative humidity 95% 4. Minimum relative humidity 10%

5. Height above mean sea level Up to 1000mtrs 6. Dust storms likely to occur March to July 7. Average No. of thunderstorm days p.a. 40

8. Average No. of tropical monsoon 4 months(Conditions) per annum.

4 months

9. Average rain fall 10cms to 100cms

4 Measured Parameters

The meter shall measure and compute Energy, Demand and other Electrical parameters on Real Time Basis.

4.1 Instantaneous Parameters

The meter shall compute the Electrical parameters i.e. Voltage, Current, Power Factor & frequency on real time basis.

4.1.1 Instantaneous Parameters

It shall display the real time data on the LCD display of Meter. The Meter shall measure the Line to Neutral Voltage for each phase. Meter shall measure current in each phase with individual power factor (lag/lead) and Net Power Factor (lag/lead) for all phases.

4.1.2 Average RMS voltage

The meter shall continuously compute the average of the RMS value of the 3 Line to neutral PT secondary voltages as the percentage of 63.51 V.

4.1.3 Average Frequency

Average frequency for each successive 15min block shall be measured and stored in 2 digit code (00 to 99) for frequency (49Hz to 51Hz). The same is computed as under:

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7 4.1.4 Net Power Factor

The meter shall compute the Net Power Factor that is the ratio of Active Power to Apparent Power.

Net Power Factor = (kW) / (kVA)

4.1.5 RTC:

The meter shall have a built in calendar in clock, having an accuracy of 3 minutes per year or better. The calendar and clock shall be correctly set at manufacturer’s works. Clock adjustment shall be possible at site using the common meter reading instrument (CMRI).

A separate internal Lithium battery back-up shall be provided for continuous operation of meter RTC for at least two years under meter un-powered conditions. The offered meters shall be supplied duly fitted with the long life battery of at least 10 years as long as total PT failure does not exceed two years.

4.2 Energy Parameters

The Meter shall measure Active (kWh), Reactive (kVArh) & Apparent (kVAh) Energy in Import/Export while power factor is lagging/leading (All 4 quadrants).

4.2.1 Active Energy

It shall measure Active Energy during Import /Export.

It shall measure the Active Energy Import/Export for each 15min successive block and the same shall be stored to the NVM at every midnight for 42 days. The harmonics shall be filtered out while measuring active energy.

4.2.2 Reactive Energy

It shall be measured while power factor lagging/leading. In addition to this reactive Energy shall also be measured in following conditions

Reactive energy lag while active energy import Reactive energy lead while active energy import Reactive energy lead while active energy export Reactive energy lag while active energy export

In the event of the RMS voltage being less than 97% of the reference voltage, the four registers above are also integrated to 4 separate reactive Low registers. In the event of the RMS voltage being more than 103% of the reference voltage, all four registers above are also integrated to 4 separate reactive High registers.

4.2.3 Apparent Energy

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8 In Import Mode

[kVAh (Import)+ = √ (kWh import) 2 + (kVArh lag import + kVArh lead import) 2 In Export Mode

*kVAh (Export)+ = √ (kWh Export) 2 + (kVArh lag Export + kVArh lead Export) 2

4.3 Demand Parameters

The Meter shall compute the Active/Apparent power (kW/kVA) in both Import & Export mode for Integration period of 15 minutes using block method.

4.3.1 Maximum Demand

The meter shall continuously monitor the demand (kW/KVA) and update the Maximum Demand for the month.The MD shall reset automatically at predefined Date & Time (Default last day of every month at 24:00hrs).

It can be reset manually through CMRI with proper password based security. 4.3.2 Cumulative Demand

The meter shall compute the cumulative Demand kVA. 4.3.3 Rising Demand

The meter shall also compute the Rising Demand KVA with elapsed time period.

5 Stored Parameters

The meter shall have a non-volatile memory to store the measured parameters as specified in Technical Specification. The meter shall store load survey data for at least 75days which shall be updated on FIFO basis. The non-volatile memory shall retain the data for a period not less than 10 years under un-powered condition; battery backup memory shall not be considered as NVM.

The Stored data shall be available through communication ports while down loading the meter using Hand Held Units for Billing/Analysis/Report Generation purpose at Base Computer Station.

5.1 Time of Use (ToD/ToU) Parameters

The meter shall have facility to register Active/Apparent Energy Import/Export and demand (kW/kVA) in 8 (EIGHT) TOD time zones. The number and timings of these TOD zones shall be programmable at site/factory. User specified tariffs shall be factory programmed in the meters.

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5.2 Billing Parameters

The meter shall have the provision to store last 6 months billing data which shall be available at the BCS for analysis. The meter shall store Cumulative Energy, Demand, Avg. power factor for billing month with Billing date/time details.

It shall store the daily consumption of energy/demand for current month at midnight for 42 days.

5.3 Load Survey Parameters

The meter shall have NVM to store 75days load survey data with Energy/Demand values for 15-min block interval.

It shall store Active/Reactive(lag/lead)/Apparent Energy/Demand in Import/Export mode. It shall have facility to store Average frequency for 15-min block and shall code it in to 2-digit value.

It shall denote star (*) when the Voltage is below 60%Vref in particular block interval on the BCS.

The data shall be available for downloading through CMRI/laptop. It is available at the Base Computing Software (BCS) both in graphical & matrix format for analysis purpose.

The BCS representation of Load survey data shall be Daily, Weekly & Monthly format.

5.4 Event/Anomaly Parameters

 To detect/log the change in configuration (i.e. RTC setting, TOD) parameters. The same is logged to the meter’s NVM.

 Shall have Self Diagnostic facility (i.e. RTC, Memory & Display check [on LCD only]). The same can be viewed on the BCS.

 The Meter shall have provision to detect & log anomaly functioning with Snap Shot details. o It shall have provision to log 200 events with data updated on FIFO basis. It shall

have at least 3 blocks/compartments to store various tamper data in different blocks. The visual alert/indication shall also be provided for present status. The occurrence & restoration thresholds are as per details in table below. All the following events are logged in the NVM with snapshot data.

5.4.1 Tampers/Anomalies 5.4.1.1 Potential Miss

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10 5.4.1.2 Voltage Unbalance

Meter shall have provision to detect the voltage unbalance when the difference between Vmax and Vmin is more than a threshold value.

5.4.1.3 Current Reversal

Meter shall have provision to detect the Current reversal in CT Phase wise. 5.4.1.4 Current Unbalance

Meter shall have provision to detect the Current unbalance when difference between Imax and Imin is more than the threshold value.

5.4.1.5 CT Open

Meter shall detect the CT open as per the threshold values. 5.4.1.6 CT Bypass

Meter shall have provision to detect the event of Current Bypass as per thresholds. 5.4.1.7 Neutral Disturbance

Injection of Spurious Signals/DC injection through Diode affecting the meter functionality shall be detected.

5.4.1.8 Magnetic Influence

Meter shall be accurate under Magnetic Influence as per CBIP report No.304. Meter shall record Energy at Vref, Imax & UPF in magnetic influence.

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S.NO TAMPER

TYPE

OCCURANCE THRESHOLDS RESTORE THRESHOLDS CONDITION

1 Link Miss Vx <25% of Vref Ix>10%Ib Vx > 40 % Vref Current Ignored First compartment 2 Magnetic Tamper

Meter Under Magnetic Influence

Meter Not Under Magnetic Influence Third compartment 3 CT Reversal Ix > 5 % Ibasic Vx >40% Vref Direction –ve Net PF > 0.1 Ix > 10 % Ibasic Vx >40% Vref Direction +ve Net PF > 0.1 Second compartment 4 Neutral Disturbance Vx<25% Vref and

Other 2 phases>125% Vref

Vx>25% Vref and Other 2 phases<72Volt 5.5 Third Compartment 5 Current Unbalance

(Imax – Imin) > 30% of Ib and Average current>20mA

(Imax – Imin) < 10% of Ib and Average current>20mA

Second compartment 6 CT Bypass Bypass Current>20% Ib Bypass Current<10 % Ib Second

Compartment 7 CT Open Ix<2% Ib and

Any one phases Current>10% Ib

Vx>40% Vref

Ix>5% Ib and

Any one phases current>5% Ib Vx>40% Vref Second Compartment 8 Voltage Unbalance Vmax-Vmin>10% of max voltage of 3-phase voltages All Voltages>60% Vref

Vmax-Vmin<10% of max voltage of 3-phase voltages All Voltages>60% Vref

First

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6 Display Parameters

The meter shall have provision to display the measured parameters on an LCD as detailed below.

6.1 LCD Details

The meter shall have a 7-segment Liquid Crystal Display with backlit to clear visualization of parameters. It shall have (7+1) digits to display the Energy & Demand values including decimal values. The right most digit shall be clearly distinguishable from other digits (small in size from others)

The values on Display shall have proper indication/Unit of Measures to identify. Annunciators to show PF (Lag/Lead), Current Direction, Phase/current availability & present Tamper status.

The three line-to-neutral voltages shall be continuously monitored, and in case any of these falls below 60%, the condition shall be suitably indicated on display.

6.2 6.2 Display on Meter

The meter shall continuously display the parameters on its LCD in auto mode. The time interval between two successive parameters shall be at least 10 sec.

The data shall also available through push (on demand) button to Display the Energy/Demand values. The display shall switch to normal (auto) mode in case of nonoperational push mode for more than 300 sec. There shall also be a provision to lock any parameter by pressing scroll up button for 5 seconds continuously.

The meter shall have provision to display the measured values during power off condition through internal battery back-up.

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6.3 Display Parameters

AUTO MODE All segment check Real Time

Real Date

Meter ID (Meter Serial No.) Bill KWH import

Bill KWH export Bill KVAH import Bill KVAH export Bill MD KVA import Bill MD KVA export Bill PF import Bill PF export

Bill Reactive High lag import when V>103% Vref Bill Reactive High lag export when V>103% Vref Bill Reactive High lead import when V>103% Vref Bill Reactive High lead export when V>103% Vref Bill Reactive low lag import when V<97% Vref Bill Reactive low lag export when V<97% Vref Bill Reactive low lead import when V<97% Vref Bill Reactive Hlow lead export when V<97% Vref

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14 PUSH MODE

Push

All segment check Real Time

Real Date

Meter ID(Meter Serial No.) Bill KWH import

Bill KWH export Bill KVAH import Bill KVAH export Bill MD KVA import Bill MD KVA export Bill PF import Bill PF export

Bill Reactive High lag import when V>103% Vref

Bill Reactive High lag export when V>103% Vref

Bill Reactive High lead import when V>103% Vref

Bill Reactive High lead export when V>103% Vref

Bill Reactive low lag import when V<97% Vref Bill Reactive low lag export when V<97% Vref

Bill Reactive low lead import when V<97% Vref

Bill Reactive low lead export when V<97% Vref

Power on hours Md reset count

last IP block active energy import last IP block active energy export Average Frequency of previous Block Average Percentage voltage

Reactive High lag import when V>103% Vref Reactive High lag export when V>103% Vref Reactive High lead import when V>103% Vref

Reactive High lead export when V>103% Vref

Reactive low lag import when V<97% Vref Reactive low lag export when V<97% Vref Reactive low lead import when V<97% Vref Reactive Hlow lead export when V<97% Vref

Active Energy Import Active Energy Export

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15 Cumulative Reactive Lag during KWh import

Cumulative Reactive Lag during KWh Export Cumulative Reactive Lead during KWh import Cumulative Reactive Lead during KWh Export Apparent Energy during KWh Import

Apparent Energy during KWh Export Instantaneous power factor

cumulative MD KVA import cumulative MD kva export Instantaneous R phase voltage Instantaneous Y phase voltage Instantaneous B phase voltage Instantaneous R phase current Instantaneous Y phase current Instantaneous B phase current Line frequency in Hz

Phase sequence Active Power( KW) Reactive Power( KVAR) Apparent Power(KVA)

MD Kw import MD Kw export MD KVA import MD KVA export

R/Y/B Phase voltage miss Voltage Unbalance Neutral disturbance

R/Y/B Phase current reverse Load bypass

R/Y/B/CT open Current unbalance magnet tamper Last Tamper Occur Last Tamper Occur Date Last Tamper Occur Time Last Tamper Restore Last Tamper Restore Date Last Tamper Restore Time Cumulative Tamper Count

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7 Communication & BCS Software:

The Meter shall have galvanically isolated optical port as per IEC: 1107 or relevant Indian standard for communication. In addition to optical port Meter shall have facility to communicate remotely through RS-232 or RS-485 port for data downloading. .

There shall be provision of passwords for online/offline data retrieval/changing configuration. Collected Data shall not be reprogrammable/modifiable by any means.

The meter shall be compatible for GSM/GPRS/PSTN communication for online/offline data retrieval at remote location.

The collected data shall be uploaded in BCS software for analysis purpose. It shall be possible to generate meter report from BCS & export it to text/Microsoft® Excel® files. User shall also be able to print the Reports.

8 CONSTRUCTION OF THE METER

Body of the meter shall be designed suitable for projection mounting. The meter should be made of high quality raw materials to ensure higher reliability and longer life. The meter should be compact and reliable in design e.g. to transport and immune to vibration and shocks involved in transportation/handling. The construction of the meter shall be suitable for its purpose in all respects and give stable and consistent performance under all conditions especially during dust storms/heavy rains/very hot days.

All insulating material used in the construction of the meter shall be non-hygroscopic non ageing and of tested quality. All parts that are likely to develop corrosion shall be effectively protected against corrosion.

8.1 SEALING OF THE METER:

Proper sealing arrangement shall be provided on the meter to make it tamper proof and avoid mishandling by unauthorised person. Sealing arrangement for at least two (2) seals on the body, 2 nos. tamper evident sticker seals between the base and cover of the meter body, two (2) seals on the terminal block cover and one seal on communication port shall be provided. Access to the working part should not be possible without breaking the seals. The polycarbonate seals shall have proper locking to avoid opening of the seal in any case by means of tampering.

8.2 TERMINAL BLOCK COVER:

The terminal block cover for the meter shall be extended transparent type, which can be sealed independently. The terminal cover shall enclose the actual terminals, the conductor fixing screws and 10mm of the external conductors and their insulation for which the terminal cover shall be of extended type. The terminals shall not be accessible without removing the seals of

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17 the terminal cover when energy meter is mounted on the meter board.

8.3 CONNECTION DIAGRAM & TERMINAL MARKING:-

The connection diagram of the meter shall be clearly shown on inside portion of terminal cover

and should not fade with time. Meter terminals shall also be marked and should appear in the above diagram.

Meter shall have a name plate clearly visible, secured against removal & indelibly and distinctly marked with all the essential particulars as per relevant standards i.e.

a. Manufacturer’s name and trademark b. Serial number

c. Type designation

d. Rated current, voltage ,frequency, PT ratio

e. Relevant IS/IEC No. along with ISI certificate mark, wherever available. f. Meter constant shall invariably be indicated.

g. Name of the owner, purchase order no. & date and month/year of manufacturing shall be printed.

h.

Guarantee Period

i. Principal units of measurement. j. Number of phases and wires k. Class index of meter

9 Accessories

The Meter shall be supplied with BCS/CMRI software CDs, one copy at each Division/sub-Division or as per requirement.

Communication Cable (Meter to CMRI) shall be supplied with each meter.

Each Meter shall have user manual with Display Parameter, Tamper Threshold & connection Diagram details.