ESV is responsible (in the State of Victoria) for the protection of underground and underwater structures from the corrosive effects of stray electrical currents – electrolysis.
Electrolysis is the effect of stray electrical currents on buried metallic structures.
Stray current corrosion is the damage that occurs when a direct current leaves a structure, such as a railway track and returns to the current source through another structure. It differs from natural corrosion in that the damage is caused by an electric current from external sources leaving the grounded metal and is independent of the oxygen concentration of the environment.
An electrolysis mitigation system is designed to reduce the effects on metallic structures of the leakage of stray electrical currents. It comprises the feeder cables, the substation equipment and drainage bonds connected to the feeders – installed to minimise the effects of stray currents – and the electrolysis box and panel at the structure connection point.
In discharging our responsibility to oversee the management of electrolysis mitigation, ESV is advised by the Victorian Electrolysis Committee (VEC).
Victorian Electrolysis Committee (VEC)
The Victorian Electrolysis Committee (VEC) consists of eight members representing:
- Energy Safe Victoria
- Train operators
- Tram operators
- Telecommunications, and
- the Oil industries
The Minister appoints the members of the VEC for a period not exceeding three years. One member is appointed by the minister as chairperson.
Part 9 of the Electricity Safety Act 1998 (the Act) establishes the Victorian Electrolysis Committee (VEC), and under section 92 of the Act the functions of the VEC are to:
- Establish and maintain standards for systems for cathodic protection and for the mitigation of stray current corrosion; and
- Provide advice to Energy Safe Victoria, on any matter related to electrolysis and the regulations relating to cathodic protection and to the mitigation of stray current corrosion, when requested to do so by Energy Safe Victoria; and
- Encourage the development of new methods and technology to increase the efficiency of systems for the mitigation of stray current corrosion.
Part 9 of the Act also contains provisions relating to Cathodic Protection Systems, Mitigation Systems and the constitution of the Victorian Electrolysis Committee.
ESV’s role in electrolysis mitigation
ESV’s Electrolysis Mitigation team is responsible for ensuring compliance with the above legislative requirements through its performance of the following activities:
- coordinating area tests to determine to extent of stray current issues within a traction substation area and determining recommendations in an attempt to minimise the effects of stray current corrosion
- routine testing of stray current mitigation equipment
- commissioning of new stray current mitigation equipment
- maintenance of stray current mitigation records
- approval, registration and auditing of cathodic protection systems
- assisting industry stakeholders with testing as required
- special electrolysis investigations as required.