The Bulgarian State Railways, founded in 1888, are among the oldest rail networks in Europe. Providing passenger and freight services, they cover more than 4,200 kilometers and connect diverse geographies - from the snow-capped Balkan mountains to the sunny Black Sea coast, from the bustling state capital Sofia to culture hub Plovdiv, and from Balkan Serbia to Mediterranean Greece.
The National Railway Infrastructure Company (NRIC), responsible for the smooth operation and maintenance of this railway infrastructure and the electrical power that supports it, was facing power quality challenges across the network.
Large varying non-linear loads are an inherent feature of electrical railway traction systems. Since the load changes dynamically and constantly, the traction power supply system draws a high amount of reactive power resulting in low power factor affecting power quality. Poor power quality is not only harmful to the traction system itself, but also prone to spreading through the supply grid and can cause disturbances to other users on the same grid. It also results in non-compliance to grid codes, leading to financial impact in the form of penalties.
"Power quality is key to improving grid reliability and helps to optimize operating costs and ensure grid code compliance. It also enhances energy efficiency, leading to lower carbon emissions, minimizing environmental impact," says Giandomenico Rivetti, Managing Director of ABB's High Voltage Products business unit, a part of the company's Power Grids business.
An efficient and cost-effective solution from ABB
NRIC approached ABB for a solution to its power quality challenge. After a detailed study of the various electrical parameters, ABB's step-less reactive power compensators PQC-STATCON were installed in the traction substations.
The PQC-STATCON technology is used to provide reactive power support for grid-based supply networks. By installing this technology at various nodes across its electrical system, NRIC will experience improved power quality and better compliance to grid codes. Further benefits are accurate and precise compensation without the need for manual intervention, voltage stability and avoidance of penalties by the grid.
PQC-STATCON and power quality monitoring equipment now installed at five NRIC substations across Bulgaria will help NRIC maintain the right power quality across its network and avoid significant financial penalties. It will also provide added benefits like reliability and availability of the supply network, energy efficiency and lower maintenance costs."
Reactive power compensator, PQC-STATCON is just one of a wide range of ABB products, systems and services that can significantly help improve power quality. As world leader in power and automation technologies, ABB offers a wide range of solutions, such as capacitors banks and harmonic filters, Static Var Compensators and FACTS devices, other power electronics based compensation systems, battery energy storage solutions and software based Volt Var Management Systems that enhance power quality in low, medium and high-voltage applications.