AC Mitigation Device
AC Mitigation Device is designed to divert alternating current from underground metal structures induced as a result of exposure to electromagnetic radiation from high-voltage power lines (power lines) and other high-voltage sources. The device allows the induced electric current to drain into the grounding device, while it does not have any effect on the cathodic protection system that is used at this facility.
AC Mitigation Device is executed in the KIP-PSS test station rack according to TU 28.99.39-085-73892839-2018 with information marking, it has a terminal panel with contact terminals, a closed cover, and an AC discharge unit is fixed in the rack.
Application
For the purpose of rational planning and use of territories and optimization of maintenance of ground and underground communication systems, pipelines are often laid in the same corridor as a power transmission line. In such cases, installation of pipeline protection devices of the AC Mitigation Device type is performed. This is due to the fact that this arrangement of highways has both positive and negative aspects.
The electromagnetic field created by high-voltage sources leads to the appearance of a longitudinal electromotive force in the pipeline network, against which there is a risk of electric shock to employees, active electrolytic corrosion processes from alternating current begin, and electrical equipment that ensures the correct operation of the pipeline system fails.
Effective protection of pipes from stray currents allows you to avoid these troubles.
AC Mitigation Device is recommended for use in places where there is a dangerous influence of power lines on the pipeline, namely:
- When the pipeline and the power line follow in parallel
- At the intersection of pipelines and power lines
- In places where the pipeline and power lines meet (move away)
The presence of a lightning protection device in the design of the AC Mitigation Device ensures the removal of pulsed overvoltages (lightning discharges) and short-term overvoltages that may occur in the event of a short circuit of the power transmission line to earth in the area of the AC Mitigation Device.
Functional Features
The device is an element of the cathodic protection system of pipelines against corrosion and has the following functions:
- Removes alternating current induced by a high-voltage power line from the pipeline through a grounding device
- Prevents leakage of the cathodic protection potential
- Allows you to measure the diverted alternating current through the transformer built into the AC Mitigation Device
- Provides lightning protection
| Name of parameters | Type 40 | Type 80 |
|---|---|---|
| 1. Maximum DC voltage operating on the pipeline, V | 15 | 15 |
| 2. Nominal diverted current 50 Hz, A | 40 | 80 |
| 3. Peak pulse current, А | 206 | 412 |
| 4. Maximum DC current leakage at the maximum permissible DC voltage operating of the pipeline 15 V, mА |
≤1 | ≤1 |
| 5. Ingress Protection rating | IP34 | IP34 |
| 6. Weight, kg, maximum | 20 | 45 |
| 7. Resistance, Ohm, maximum | 0.6 | 0.3 |
| 8. Service lifetime | 20 | 20 |
| 9. Warranty period, year | 5 | 5 |
