Electricity and Control September 2021

COVER ARTICLE

Locally produced transformers for renewable energy plants

A rmCoil, among other South African transformer man- ufacturers, is involved or ready to become involved in the renewable power producer market, especially now that there will be more renewable projects coming up over the next few years for South Africa and neighbouring countries. At ArmCoil we recognise that smart costing and packaged technical solutions are in high demand for these producers, for inverting dc to ac voltages. Such solutions typically include a transformer, inverter and various protection and monitoring devices, packaged as a unit mounted onto a steel structure or inside a weather-resistant container. Depending on the size of the plant, applications will vary in power ratings for PV or wind driven generation plants. The rated power range required in transformers for PV self-generation plants ranging in scale from 10 MW to 100 MW is typically designed to be 2.5 MVA, 3 MVA and 6 MVA at 33 kV. Hence for a 10 MW application, there are standardly four 2.5 MVA distribution transformers. The num- ber of distribution transformers is also dependent on their locations, cable lengths and grid layout, as the cables play an important role in determining costs and other factors. Renewable energy plants convert power from dc to ac by means of inverters, to feed into the utility grid. The trans- formers and inverters required for PV and wind generation plants have been and can be manufactured in South Africa, to meet high technical specifications and project comple- tion demands. Energy storage for renewable power producers in South Africa is largely non-existent or rare and would rely mainly on battery energy storage systems. For large renewable power producers, one of the more favourable storage facilities could be in hydropower, in pumped storage schemes, where during the day water is pumped into a top dam and, during peak times, the water is released to drive power generation turbines, when the renewable power producers are effectively off-line. However, in most cases, renewable power plants are quite remote and seldom close to any pumped storage scheme. They are reliant on natural weather conditions – clear, sunny and windy days. When the weather is overcast, PV plants do not produce much power. ArmCoil is well positioned in the medium voltage market and has gone from strength to strength over the past 20 years in terms of product, skills and service development where the company boasts its niche transformer and miniature substation manufacturing capability, fully equipped repair facility and on-site maintenance division. There are not many service providers in South Africa who can offer centralised manufacturing supply, instal- lation and commissioning of transformers and miniature substations on a national and international level. ArmCoil has been doing this for years with a proven track record of success across the African continent.

Most large renewable power producers are in remote areas with logistical challeng- es to access their plants; some are situat- ed in harsh climatic environments where temperatures are quite extreme. ArmCoil is technically and commercially capable and fully equipped to assist with on-site main- tenance and parts for these remote areas and to offer medium- to long-term service level agreements which can increase the duration of product life expectancy and de- crease or prevent downtime. It is not uncommon for ArmCoil to be involved in replacing, maintaining and up- grading various OEM equipment across South Africa and Africa. This is due to many large OEMs not having local offices to sup- port their imported products such as trans- formers, protection devices for different types of transformers and other protection or monitoring devices.

Morne Bosch, General Manager - Sales & Marketing at ArmCoil.

It is important for large power producers who are in- vesting in the country to take advantage of South Africa’s competitive local transformer and miniature substation manufacturers, repairers and on-site maintenance service providers. We offer in depth expertise and support. ArmCoil holds three ISO accreditations – on environ- ment, quality and health and safety management systems – which confirm our commitment to our clients. □

Over the past 20 years ArmCoil has established itself as a well- respected local manufacturer of transformers and miniature substations.

For more information contact ArmCoil. Email: morneb@armcoil.co.za Visit: www.armcoil.co.za

3 Electricity + Control SEPTEMBER 2021