AN OVERVIEW OF THE NIGERIA ELECTRICITY METERING CODE

ICEPT CONFERENCE, ABUJA.OCTOBER 14TH- 15TH, 2008

By

Engr. Tasiu Wudil, Engr. Mohammed Imam, Sunday Obi & Khadijat Akanbi

Engineering, Standards and Safety DivisionNigerian Electricity Regulatory Commission

Outline of Presentation

Introduction General Conditions Grid Metering Code (GMC) Distribution Metering Code (DMC) Conclusion

1. Introduction

Legal Mandate of the Code

Section 32, subsection 2b and Section 81,subsections 1c and 2 of the Electric PowerSector Reform Act (EPSR) 2005;

- mandates NERC to develop and approve the operating codes for the safe, secure and reliable measure and recording of energy production and utilization.

Reasons for the Code Facilitate the need for modern, effective

metering system to account for power and energy entering and exiting the transmission and distribution networks and consumed by the customers.

Ensure the financial viability of the electricity industry after the unbundling of the generation, transmission and distribution sectors.

Ensure safe operations and usage of the metering system in the electricity industry.

Composition of the Metering Code

General Conditions

Grid Metering Code (GMC)

Distribution Metering Code (DMC)

General Conditions

Disputes-Any dispute relating to meters or metering equipment which will affect settlement and or any payment to be made or received, shall be dealt with in accordance

with the relevant disputes procedure.Disputes such as siting of the Commercial Metering Systems, technical specification for meters, metering equipment, or the data collection system e.t.c shall be referred to the Metering Committee.

General Conditions- Contd

Metering CommitteeThe membership of the committee cuts across the industry, representatives of meter manufacturers, instrument laboratories and NERC as observer.

The Chairman of the Committee shall be elected by the Metering Committee from among its members and the Market Operator shall be the Secretary of the Committee.

2. Grid Metering Code (GMC) Specifies the requirement for the metering

of the participant’s connection point on the Transmission and Distribution Networks.

It covers interchange of energy and power:- Entering and exiting from the transmission

network Entering and exiting from the distribution

network at any participant’s connecting point.

Metering Requirement Commercial Metering System are

installed to measure active and reactive energy at each connection point on the Transmission and Distribution network.

Connection points are classified according to type, as shown in Table 1, below.

Classification of GMC Types of Connection Points

Type 1

Type 2 Type 3 Type 4 Type 5 Type 6

Between a Generator unit/group with a connection capacity equal to or greater than 10MW and the Transmission Network

Between transmission network and a Distribution network.

Between Transmission Network and an Eligible Customer, with a connection capacity equal to or greater than 10MW

International Connection

s

Between two Distribution Networks of different licensees

All other connection points

Ownership and Associated Obligations

Owner’s ObligationThe relevant owner shall be

responsible for installing and maintaining his

meteringequipment at the Connection Point, unless the User agrees with the MO

otherwise.

User’s Obligation The User who owns the substation shall

provide the MO with: - 24 hour unrestricted access to the facilities where the Metering System is located. - adequate space for installing communications devices

- reliable power supplies

Market Operator’s Obligation

The MO shall be responsible for approving the initial design, testing, commissioning and sealing of any Commercial Metering System.

The MO shall maintain a register of all Commercial Meters for settlement purposes at all Connection Points.

Certification,Calibration and Testing of Metering System User’s Obligation - Individual user shall ensure the

certification, calibration of meters and metering equipment by an approved Metering Test Station in Nigeria.

- Users shall prepare, calculate, assess and validate and keep appropriate records of meter readings.

Market Operator’s Obligation

The MO shall be granted access to the Metering Equipment upon reasonable notice, to inspect any adjustments made or to attend any tests or inspection required.

The MO shall periodically check meters to ensure that the meters are operated within accuracy limits.

NERC’s Obligation

NERC shall approve the adequacy (accreditation) of any certification done by the meter manufacturer, which may require additional test or verification by an authorized Meter Test Station before usage.

Security and Data Access

Market Operator’s Obligation - Commercial Meters shall be

sealed after tests or inspections have been carried out.

User’s Obligation

Each User shall arrange for the Metering Equipment to be secured and sealed by the MO.

Ensure only personnel with the right permission have access to the Meters and Metering Equipments.

Owner’s Obligation

Only the owner can change data and the settings of the Metering Equipment but in the presence of the MO, associated user, authorized representative or with the written agreement of the MO or the associated user( This is in respect to commercial metering).

Distribution Metering Code (DMC) Specifies the technical and operational

criteria, including the procedures to be complied with by the distribution company in carrying out its metering responsibility for the customers of the distribution system.

The distribution metering code covers interchange of energy and power:-

Entering and exiting the distribution network at any customer’s connection point. Provided the customer is not a participant.

Application of DMC

Apply to all Distributors and Users of the Distribution Networks e.g. customers connected to the LV, MV distribution network and directly connected generators (provided they are not participants in the market).

Installation and Replacement of Metering Equipment Distributor’s Obligation - The Disco own, install, verify, operate,

maintain, inspect, replace all Metering systems at metering points on the Distribution System.

- The Disco shall notify the user in advance of any replacement, unless that replacement is provided as part of urgent metering services.

Standard Metering Systems These shall contain a Meter or more than

one Meter, each of which is certified and complies with the standards stated in the DMC.

Meters and Metering Equipment shall have a minimum service life of 10 years without maintenance from date of manufacture. The maximum service life of Meters and Metering Equipment shall be as specified by the manufacturer of such equipments, but in any case not longer than 20 years.

Alternatives to Standard Metering Systems

Upon the request of a User, the Distributor may arrange to install a check meter, or additional features or equipment in the check meter provided that:

The User agrees to pay the full costs of the additional features or equipment.

Alternatives to Standard Metering Systems….contd

The additional features or equipment are compatible with the rest of the Metering System and do not lead to any degradation of the capability of the Metering System that would cause the Metering System to fail to meet any standards contained in the DMC.

Technical Requirements and Accuracy of Meters Discos Obligation - The Disco shall ensure that the accuracy

of each Meter in each Metering System is certified by an authorised Meter Test Station and meets the applicable accuracy limits and conforms to the relevant IEC standards or any equivalent Nigerian Standards.

Certification and Tests (Certification of New Installations)

NERC’s Obligation - Every meter model to be used in a

Metering Installation shall be certified by National Meter Test & Calibration Laboratory (NMTCL) or any other body as may be approved by NERC to perform these Type Tests.

Certification of Existing Installations

Disco’s Obligation To obtain NERC’s certifications, the

Disco shall submit to NERC, within the first twelve (12) months of the Effective Date of this DMC, all supporting documentation to show certification of its metering equipment.

Certification of Existing Installations…..contd NERC’s Obligation - NERC will evaluate the submitted

documentation, require clarifications and conduct independent analysis which should include testing, by an authorised Meter Test Station, of specific samples of the Meters or Metering Equipment, before issuing or rejecting the required certification.

Re- Certification

Before the certification of a Metering Installation, or of any of its components, expires, the Metering Installation should require re-certification, by an authorized Meter Test Station accredited to perform Calibration Tests certifications.

Duration of Metering Systems Inspection Disco’s Obligation The Disco shall ensure that each

Metering System is inspected according to the following Table:

Type of Metering System

Frequency

Medium Voltage Once every year

Low Voltage, including PPM

Once every 3 years

Duration of Metering Systems Calibration and Tests Disco’s Obligation The Disco shall ensure that each

Metering System is tested and calibrated by an authorised Meter Test Station according to the following Table:

Duration of Metering Systems Calibration and Tests…contd

S/N Type of Metering System

Frequency

1. Medium Voltage

Connection Capacity above 10 MW

4 years

Connection Capacity between 1 and 10 MW

8 years

Connection Capacity below 1 MW

8 years

2. Low Voltage, including prepayment

8 years

Duration of Metering Systems Calibration and Tests…contd User’s Obligation - The User may request the Disco to

carry out inspection and or testing, provided that the User pays the cost of the test.

-The User shall grant access to NERC inspectors to carry out inspections and or tests.

Duration of Metering Systems Calibration and Tests…contd

NERC’s Obligation - NERC may carry out unannounced

inspection and or test, utilizing an authorised Metering Test Station if considered suitable.

Faulty Metering Equipment Disco’s Obligation - If a Metering System fault occurs, the

Disco shall provide Urgent Metering Services to repair or replace the Metering System as soon as is reasonably practicable and in any event within two working days of the Distributor discovering that the fault exists.

Access to Metering Systems

User’s Obligation -The User shall grant access to the

Distributor to enable the Disco to fulfill its obligations under the DMC.

Security of Metering Systems

Disco’s Obligation - The Disco shall maintain the

security of the metering data stored in or obtained from each Metering System.

- Appropriate seals shall be applied to each Metering System which is subject to NERC approval.

Meter Reading and Data Management Disco’s Obligation - The Distributor shall schedule at least

once in four (4) months reading for all manually read meters.

- The Disco shall maintain a metering data registry that contains usage data for each User and data required for settlement purposes in respect of each Metering System.

Conclusion The Metering Code is a live document which

changes with new requirements and advancements in the use of modern meters.

Modern accurate metering systems shall be deployed across the industry to measure and record energy production and utilization.

Ensure financial viability of the electricity industry after the unbundling of the Nigeria Power Sector.

THANK YOU