Sasol Mining chose the highly flexible ABB Relion® protection relays for their new substation at the Syferfontein mine in South Africa. The wide functionality, large event and fault recording capabilities, reduced footprint, as well as cost reductions were key factors.
Sasol Mining is part of South African integrated energy and chemical company Sasol, undertaking the coal mining operations. Sasol Mining operates six coal mines that supply approximately 40 million tons per annum of thermal coal feedstock.(1) At the company’s largest colliery, the Syferfontein mine in the Secunda area, Sasol Mining identified that the ventilation shaft was not sufficient to ensure the required aeration of the mining district. To ensure uninterrupted power supply to a new ventilation shaft, they needed a new substation.
In underground mining, ventilation systems are of paramount importance to ensure safe working conditions for people. Ventilation systems need to run continuously for 24 hours a day, throughout the year, which means uninterrupted power supply is a key requirement. The energy demand is significant and ventilation systems are currently the largest consumers of power in underground mines, accounting for as much as 50 percent of energy use(2).
For the new substation that feeds the new ventilation shaft, Sasol Mining chose a protection and control solution with ABB’s Relion® relays from the product family’s 615 and 620 series, as well as the all-in-one protection relay REX640 to be installed in the medium-voltage switchgear. This is the first installation with ABB’s Relion® protection and control relays for Sasol Mining.
“A key consideration for us when deciding in favour of the Relion® relays was that they offered all the functionality we need,” said Divesh Ramasur, senior electrical engineer at Sasol Mining. “They are also flexible and offer large event and fault recording capabilities.”
Sasol Mining chose these protection and control relays because they offer the needed circuit breaker control functions and have arc flash protection embedded for increased safety. They also have simpler GOOSE (generic object-oriented substation event) protocol utilisation and all have the R/L (remote/local) switch available on the relay face plate for easier operation. Further, the customer chose Relion® 620 series relays for motor protection. These relays offer stall protection functionality and also thermal overload protection considering the actual starting time of the motor.
The installation of Relion® relays has resulted in cost reduction and reduced switchgear footprint. “With REX640 we can use only one relay for transformer protection, whereas earlier we had to use many different relays to achieve the same level of protection,” said Ramasur. “The REX640 relay has many protection functions available for transformer protection, such as low impedance differential protection, low impedance restricted earth-fault protection, sensitive earth fault protection, and tap changer control all integrated into the relay. On top of that, it has many binary inputs and outputs, and the relay can incorporate many analogue inputs, too.”
To learn more about ABB’s digital substation products, please visit go.abb/digitalsubstations.
1) https://www.sasol.com/about-sasol/strategic-business-units/energy-business/sasol-mining
