Distribution Transformer Metering A Diagnostic Tool

1
Distribution Transformer Metering -A Diagnostic
Tool

• By
• Manohar Bagde
• Executive Director (Retired), MSEDCL ,Mumbai
• Advisor (Power), Feedback Ventures, Mumbai

2
Structure of Presentation

• Why DT Metering ?
• 5 Components of DT Metering
• A Case study MSEDCL
• Identification of Problems
• Possibilities Data Usage
• Concerns
• Conclusion

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Why DT Metering?
4
5 Components of DT Metering System
Consumer Metering
Distribution Transformer
Feeder 1
Current Transformer
Feeder 2
R M S
Meter
Consumer Indexing
(Remote Metering System)
Software Programme for Data Processing
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LT Current Transformers

• As per CEA (Installation Op. of Meters)
  Regulations, 2006
• Accuracy Class should not less than that of
  associated meter
• Generally Ring Type CTs are used ,which is not
  desired
• Epoxy Resin Cast CTs are better
• Avoid use of Duel Ratio CTs
• Ensure proper CT Ratio Polarity
• Placement of CTs Important Role
• CT Meter embedded with DT

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Placement of CTs outside DT
1
3
2
4
5
7
DT Energy Meter RMR

• No uniform standard practice adopted by utilities
  
• prior to publication of CEA Regulation
• Important provisions of CEA( I. Op. of Meters)
  Regulation 2006
• Minimum 0.5s accuracy class
• Memory at least 35 days
• MRI downloadable
• Data Port for Remote Transmission
• All Type , Routine Acceptance tests to be
  carried out
• as per applicable IS,BS or IEC
• Periodical testing at site at least once in 5
  years
• Elimination of Scale Factor or Multiplying Factor
• Remote Meter Reading - to eliminate human
  element

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Consumer Meters

• Why important ?
• DT loss Units sent Units billed
• Important provisions of CEA Regulations
• Quality Control Testing at manufacturers works
• Standard Installation Practice
• Periodic testing
• All meters should be static
• Utility should replace faulty meters quickly

Utilities Should Provide Quality Meters
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Consumer Indexing

• Consumers to be identified with DT,
• by walk down survey
• To verify Billed, Unbilled, direct connections
• Meter reading routes to be modified as per
• walk down survey
• Codification of DT
• Reading of DT meter consumers fed through
• the DT to be taken on the same day

GIS Mapping of Network up to Service Line is a
Powerful Tool
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Software program for Data Processing

• Software should automatically pickup DT meter
  reading associated consumer billing data from
  respective reading repository process to give
  DT-wise energy audit results
• Software should take care of eventualities viz.
• premises locked
• meter not available / faulty
• unmetered consumers
• seasonal billing cycle diversities
• billing period variation for loss calculation on
  monthly basis
• Reports to be generated analyzed for taking
  corrective action

Good Software Program Improves Utility of System
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A Case Study - MSEDCL
Source http//mahadiscom.co.in
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Identification of Problems

• Wrong CT polarity
• Loose current and / or voltage connections
• Recording wrong CT ratio
• Incorrect consumer indexing
• Consumers with different billing cycles on the
  same DT
• Improper assessment in cases of eventualities
  such as meter faulty, stopped etc.
• Shifting of load on nearby DT, in case of failure
  of DT
• Improper assessment of un-metered Consumption
• Intentional human intervention

Problems should be Identified Rectified
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Possibilities of Meter Data Utilization
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Concerns

• High rate of failure of meters in some utilities,
  therefore
• Better Technical Specifications Stringent QC
  measures - by utilities
• Quality Meters - by manufacturers
• Optimum design of DT Metering System
• Resistance from staff
• Inadequate tools, equipments agencies at the
  disposal of Field Engineers
• Present low level of DT metering by utilities
• Sharing of DT Energy Accounting results with
  stakeholders by utilities
• Encouragement through incentives by Regulators
• Creating awareness by NGOs consumer groups

Improvement in Program Planning Implementation
Strategy
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Conclusion

• DT Metering is a must tool for a distribution
  utility to
• identify high loss areas
• to increase revenue
• Would be more meaningful, if
• Concerns are addressed promptly adequately
• Timely actions are initiated for loss reduction
  measures
• Data is used for Energy Audit other Engineering
  decisions to improve reliability in system.

DT Energy Audit is Key to Business Success of a
DISCOM
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• Thank You