The Gulf Cooperative Council Regional Committee (GCC CIGRE) is an affiliate of the International Council for Large Electric Systems (CIGRE) and a leading group in GCC countries when it comes to technical, economic and other aspects of power grids. Among its main objectives are facilitating exchange of field experience and latest technologies between various stakeholders.
As part of the ongoing activities of its technical committee, GCC CIGRE organizes a conference held in a GCC member country and the 12th such GCC Power event was held in Doha this past November. INMR Contributor, Raouf Znaidi attended the event and reviews two of the papers presented.
The technical program of this conference included tutorials, panel discussions and plenary sessions. Each discussed several papers submitted by the research departments of GCC, Arab and international power companies, operators and power plants in addition to those by academics invited from abroad.
What characterizes each GCC Annual Conference, with its more than 50 papers and 35 poster sessions, are awards presented to those having greatest relevance to the current needs of GCC power systems. For example, Paper (B301) GCCIA Pollution Test Station: Field Assessment and Test Station Results was among those receiving such an award. This paper and another are summarized below.
Paper B 301: ‘GCCIA Pilot Pollution Test Station: Field Assessment & Test Station Results’
It is widely accepted among experts in the testing field that existing standardized test procedures do not always simulate in the laboratory the severe and complex service conditions that can lead to pollution flashovers in the field.
A naturally polluted energized test station that also monitors weather parameters is therefore among the predictive approaches now recommended within CIGRE and supported by researchers as well as power utilities worldwide. Due to the valuable data they yield on real outdoor performance of insulators, such test stations are regarded as the most cost-effective technique to compare the service performance of different insulator designs under natural pollution conditions.
Test Set-Up & Expected Results
The paper reported that the energized test station is representative of the severe natural service conditions prevailing in the eastern part of Saudi Arabia. It also emphasized that, apart from being able to better assess optimal insulator designs for this environment, another of the objectives of this work was to enhance the knowledge and expertise among GCCIA technical and maintenance staff, including:
• More efficient field training;
• Better understanding of external insulation & relative performance under different types of severe service conditions;
• Improved knowledge of different insulator types, materials & production techniques.
Apart from providing site pollution severity (SPS), the energized pollution test station also provides valuable information covering:
• Pollution accumulation mechanisms;
• Deposit rate of soluble and non-soluble contaminants;
• Particle size and pollution distribution on insulator surfaces;
• Pollution characterization through analysis of its chemical constituents, including salt density & conductivity;
• Identification of different pollution types (A or B);
• Site pollution severity assessment, based on ESDD & NSDD;
• Classification of site pollution severity, from very light to very heavy;
• Ranking, by order of merit, of different insulator profiles & materials under the same severe service conditions;
• Selecting optimal insulator profiles & materials for each specific GCC region;
• Detecting, over a relatively short test period, examples of material degradation, poor design or improper manufacturing;
• Identifying critical wetting mechanisms (salt spray vs. humidity vs. light rain vs. dew);
• Raising alarms to alert technical staff in charge of line and substation maintenance whenever critical levels of pollution have been reached at given sites;
• Optimized line maintenance programs & inspection techniques, based on realistic field measurements, to avoid flashover risk due to critical pollution accumulation;
• The first pollution map of the existing GCCIA network.
Paper B 303: ‘Standardization of Conductors for 380 kV Overhead Transmission Lines in Saudi Arabia’
The conductor is viewed as one of the most important components of an overhead transmission line and normally accounts for between 30 and 35% of its total capital cost. It is therefore important to always select an optimum conductor.
In order to standardize on one out of the three existing conductor sizes, a Committee was formed within the grid operator of Saudi Arabia, comprising members of different departments, including Standards & Specifications, EHV Engineering & Design, EHV Network Planning and Grid Maintenance.
Expected Cost Savings
The Capital Budget Plan for the 10 years from 2016 to 2026 has anticipated about 37,000 kilometers of new 380 kV transmission lines will be added to the existing network in Saudi Arabia. Using ACSR/AW Condor conductor, the overall savings will be about 385 & 1239 million Saudi Riyals [1000 SAR = US$ 266] respectively compared to AAAC & ACAR type conductors. Reductions in annual costs will be about 15 & 21 million Saudi Riyals, respectively (i.e. about US$ 4 million & US$ 5.6 million).
Other Benefits of Standardizing Conductors
• Reduced design work & lead time;
• Reduced inventory costs & need for warehouse space along with reduction in material procurement work and control of stores;
• Improved ease of purchasing and faster deliveries;
• Improved emergency repair;
• Reduced quality control (i.e. to assess product quality, reduce numbers of vendors) as well as in errors during construction and maintenance;
• Greater economies of scale in system construction and operation.