(English) Guidelines for Computation

SEM Hand book

Special Energy Meters (SEM) in NR:

1. Details of SEMs installed in NR are available at
   Master File . MASTER file contains following SEM details.
   1. Meter ID
   2. CT Ratio
   3. PT Ratio
   4. Type of Meter
   5. Location of Meter

Use Notepad to open raw Data, Processed and Entity wise SEM data files.

Raw SEM data:

1. As per IEGC 6.4.21 Encrypted SEM data from all concerned stations is sent to NRLDC every week by Tuesday for data validation and energy accounting.
2. Encrypted SEM data is decoded at NRLDC using software’s provided by SEM vendors.
3. Decoded SEM data at NRLDC end is used for Energy accounting and is available in text files.
4. Decoded SEM data of all meters in NR is available at https://nrldc.in/commercial/sem-data/current-week/raw-data/
5. Raw SEM data is uploaded in website every week by Friday after completion of energy accounting.

Processed Data:

1. As per IEGC 6.4.21 Encrypted SEM data from all concerned stations is sent to NRLDC every week by Tuesday for data validation and energy accounting.
2. Encrypted SEM data is decoded at NRLDC using software’s provided by SEM vendors.
3. Decoded SEM data at NRLDC end is used for Energy accounting and is available in text files.
4. Decoded SEM data of all meters in NR is available at https://nrldc.in/commercial/sem-data/current-week/raw-data/
5. Raw SEM data is uploaded in website every week by Friday after completion of energy accounting.

Entity wise SEM data:

1. Entity wise Injection/Drawal data is available at Net Injection of ISGS & BBMB & Net Drawal of States
2. Each entity wise file contains
   1. Master frequency data(In 2 digit Frequency code format) Actual frequency = 49.5 + (Frq Code/100)
   2. SEM data of lines from which Injection/Drawal is computed
   3. Total Injection/Drawal of an entity
3. Philosophy of Injection/Drawal Computation:
   1. The sign convention of power flow recorded by meters is positive for power flow out of bus-bar and negative for power flow into the bus-bar.
   2. Net injection/drawal at any location is algebraic sum of meters (including sign) on all feeders/ICTs/GTs listed with that location.
   3. Net drawal of State Utilities would be algebraic sum of drawals at all the locations listed for that utility.

Discrepancy Report:

1. Details of Discrepancies observed in SEM data during energy accounting is available at Discrepancy Report
2. Weekly discrepancy report is uploaded in website every week by Friday.
3. Discrepancy report consists of following details:
   1. Details of meters replaced with standby/check meters due to non availability of SEM data at NRLDC.
   2. Details of meters replaced with standby/check meters due to discrepancy/under recording of main meter.
   3. Details of adjustments done in main meter data due to discrepancy in few blocks.
   4. Details of Time drift in SEMs.