Problems which had been experienced in pre-pool co-operative projects gave impetus to the establishment of the SAPP. The Operating Sub-Committee (OSC) formed working groups on various aspects, such as telecommunication, measurement and control (TMC) and operations.
Right from establishment of the OSC, members participated constructively to reach the standard of operation which has been attained so far. Early operating problems arose but most were resolved amicably under the guidance of this sub-committee, with only a few still outstanding. The OSC believes that regional co-operation in the industry has improved greatly and is a source of pride for SAPP.
SAPP Operating Guidelines - One of the first milestones for the OSC was been the preparation and submission of the SAPP Operating Guidelines, which were then accepted by the Management Committee.
Co-ordination Centre - The OSC implemented an interim co-ordinating centre to carry out limited functions, including the compilation of monthly reports. BPC was elected by the operating working group to be the pioneer co-ordinator, a function it carried out for sixteen months; the OSC, however, eventually recommended that the co-ordination centre should be located in Harare, Zimbabwe. This was done and the coordination centre used to report to the OSC chairperson up until the Coordination Centre Board was formed.
Trading - Some energy trading was conducted by member utilities during the early period (August 1995 - March 1997). The trading transactions and procedures were specified by the Agreement between Operating Members and the SAPP Operating Guidelines. The OSC later formed the Markets Working Group which in 2007 evolved into a full sub-committee.
Functions of the OSC-Functions of the OSC are detailed in the SAPP Agreement between Operating Members.
Telecommunications- In the early period, there was a basic communication network between all the member utilities except SNEL, but the quality and availability was not always acceptable and required attention from the telecommunication experts in the region. The OSC produced minimum requirements for telecommunications for implementation by the TMC. It was noted that almost all utilities had installed Internet services. Later own, the OSC, through the telecommunications working group, installed a VSAT telecommunications network among the three Control Areas (Eskom, ZESA and ZESCO) and SAPP coordination Centre in Harare. From the year 2000 the SAPP embarked on a project of linking all operating members with optic fibre. The project was expected to be commissioned by 2013.
Automatic Generation Control- Automatic generation control (AGC) has been successfully installed and operates in the 'tie line" bias mode under normal operating conditions by ZESCO, ZESA and Eskom. This has greatly improved system control and inadvertent energy management on the Southern African grid.
The OSC is encouraging all members to either purchase AGC or affiliate to a control area so as to improve interconnections and manageability. It also stressed the importance of having all regional tie lines in service, wherever possible, to increase system reliability, stability and mutual support.
Frequency Control Performance - The power oscillation phenomenon was discussed in June 1996; after taking into account financial implications and technical limitations, an agreement was reached on frequency control through a negotiated target of at least 90% within the frequency band of 49.95Hz and 50.05Hz. Initially the set target was achieved, however there were problems in achieving this.
SAPP SCADA system- In 2012 the OSC installed a SCADA system at the SAPP coordination centre in Harare for monitoring of tie-lines and some key transmission and generation equipment. The SCADA employed inter control centre protocol (ICCP) for sharing data among Control Areas. The SCADA is only for monitoring and not controlling or operating any switches or circuit breakers.
Challenges and Opportunities- The more interconnections there are the more trading opportunities and operational challenges and trading opportunities are likely to arise, for which the OSC will have to find solutions; some of those currently under consideration are:
- implementation of the SAPP training programme for system controllers
- finalisation of the study on power oscillations on the interconnections
- non-compliance with the Operating Guidelines or other agreed operating standards
- implementation of control area services charges
- implementation of the methodology of handling inadvertent energy based on Area Control Error (ACE)
- revision of the SAPP Operating Guidelines
- installation of monitoring and reporting of quality of supply on all interconnectors