Static VAR Compensators (SVCs) Facilitate Electrification Of Pipeline Compressor Stations

Demands on pipeline infrastructure are growing. Modernizing the nation’s infrastructure requires boosting existing capacity and providing new lines where additional transport is required.

Modernization also requires mitigating voltage disturbances, emissions and noise and upgrading thousands of aging compressors.

Pipeline operators are increasingly looking to Static VAR Compensator (SVC) solutions to stabilize voltage disturbances stemming from the operation of large motors at compressor and pumping stations. SVCs help to maintain stable pipeline operation by eliminating power producer and customer-side voltage sags and flicker, providing a cost-effective alternative to building new infrastructure.

One of North America’s largest energy companies recently deployed four SVC solutions to modernize its distribution network and improve pumping station performance for a major crude oil pipeline. The pipeline deploying the solutions uses multiple motors rated at 4,000-5,000 horsepower at its pumping stations to transport more than 400,000 bpd. The SVCs eliminated the need for transmission system upgrades at each of the pumping stations that would have taken months to complete at a cost of millions of dollars.

Gas Transmission Retrofit

Most natural gas pipelines were originally designed to operate using gas-driven compressors at collection stations. Using some of the gas-fired compression equipment is becoming a challenge because of air pollution-permitting requirements, high maintenance and age. The transition to electrically driven compression required natural gas pipelines to develop entirely new skills. Pipeline operators today need to not only understand the functioning of medium voltage electric motors, but also the process of specifying, acquiring, installing and maintaining large motors.

Faced with the need to acquire this new set of engineering and operating skills, the pipeline industry is rising to meet the challenge. Reflected in the upgrade of older installations to electric technologies, the industry has gained a deeper appreciation for the increased efficiency and availability of electric drives, as well as for their simple maintenance. Operating economics are driving pipeline operators toward the use of higher capacity electric motors for compression and, at the same time, are reducing the number of compressor stations. Motors in the 2,000-4,000 hp range or larger, operating at 4,160 volts, are becoming commonplace at very large compressor stations, which increasingly are using 13 kV motors in the 8,000-15,000 hp range.

One advantage of these electrically driven compressors is the ability to increase pipeline operating pressures and throughput. That leads to lower unit costs. Flow control is more flexible and precise because the motor speed can be optimally adapted to the process.

Conversion to electrically driven compressors does bring one potential disadvantage. Starting large electric motors places a major strain on electric distribution circuits. Where the “voltage sag” that accompanies the start of a proposed large motor is too great, the electric utility supplying the power may immediately terminate electric service.