PRESENTATION BY

ING JOSEPH WIAFE

MEMBER GNEC

GHANA POWER SYSTEMSTANDARDISATION AND ITS

CHALLENGES

Introduction - Profile of Ghana

� Located in West Africa and is bordered by Cote d’Ivoire, Togo and Burkina Faso

� Population of 22 million

� Major exports are cocoa and gold and recently discovered oil along the coast of Ghana

Ghana Power System

� Has about 2500MW installed capacity

� About 1400MW of new plant under construction

� Peak demand is 1500MW

� Has about 5000KM of transmission line

� Interconnected to power system of Cote D’Ivoire, Togo, Benin and Supplies power to bordering towns of Burkina Faso

Power Sector Reforms

¡ Independent power producers will be allowed into production of electricity in Ghana

¡An Electric Transmission Unit (ETU) will be created which will be independent of the producers and its purpose will be to transport electricity from the producers to bulk consumers

¡Various distribution companies will be created to distribute power to final consumers.

¡An independent system operator will be formed.

Activities so far

� Establishment of Energy Commission, PURC and NED

� The ETU has been created and is functional. It is known as the Ghana Grid Company Ltd (GRIDCo)

� There have been the introduction of IPPs who have started to supplying electricity to the grid.

� The independent distribution companies are not yet established.

� The independent system operator is yet to be established.

Ghana Grid Code

� This is supported by an act of parliament, Act 541.

� The National Electricity Grid Code of Ghana establishes the regulations, requirements, procedures, practices and standards that govern the development, operation, maintenance and use of the high voltage transmission system in Ghana

Ghana Grid Code-Contd

� The Grid Code of Ghana describes the responsibilities and obligations associated with all the functions involved in the supply, transportation and delivery of bulk electric power over the National Interconnected Transmission System. These functions include those of the transmission operator, transmission asset owner(s), Wholesale Suppliers, Distribution Companies and Bulk Customers.

Structure of the code

� From a functional view rather than organizational perspective

� Conditions of Transmission Licence;

� Standards of Performance for Public Utilities; and,

� Technical and Operational Rules of Practice.

Standards for performance

Standards set for power quality include

� Voltage limits during Normal state, Alert state and emergency state. Values of 5%, 10%,10%

� Voltage unbalance, voltage harmonics, voltage flicker

� Reactive power supply and power factor as well as system frequency limits. Frequency variation of 2%

Performance indices

Some performance indices used include

� System average interruption duration index (SAIDI)

� System Average Interruption Frequency Index (SAIFI)

� Index of transmission reliability (ITR)

Provisions from IEC Standards

Metering Standards

� Voltage transformer – Compliance with IEC 60044 standard

� Current transformer – Compliance with IEC 660044 standard

� Meter specification that comply with current version of IEC 60687 and IEC 61268

� Minimum pulse frequency shall comply with IEC standard

Provisions from IEC Standards

Other IEC provisions are

� All Symbols used in Electrical Diagrams shall be in accordance with IEC 60617 Standards as updated

� Participants shall comply with the applicable IEC and ITU standards for SCADA and Communication equipment

� The short circuit currents shall be calculated in accordance with the IEC Standards 60617 or their equivalent national standards.

Domestic power supply

� Domestic supply is genrally 220V/400

� Voltage regulation is 5 %

� Frequency variation of 2%

� Metering accuracy is 2%. Being changed to 1%.

� Grounded neutral

� Multiple neutral grounding for shieldwire areas

Challenges

� Major challenge is to ensure that the provisions of the Ghana Grid Code and the WAPP operating manual do not conflict

� Another major challenge is the funding required to expand and upgrade the power system to meet the increasing load and also the reliability and operating standards required by the Grid Code.

Conclusion

� Ghana has established a code that governs its grid system and this conforms to international best practice

� It is expected that compliance with the provisions of the Grid Code will enhance system stability and reliability

� This will bring in discipline in the operations of the power sector and will ensure a safe reliable supply of electricity for its industrial growth

� It is expected that more IPPS will participate in the Ghana power system following the promulgation of the Grid Code

THANK YOU