Phase-shifting transformers
Creating balance within and between networks
In power grids, phase-shifting transformers provide active power flow control. By enforcing or blocking loads, they not only improve the stability and flexibility of grids but also help grid operators get the most out of existing hardware. Phase-shifters are available in a range from ≤ 2000 MVA and ≤ 765 kV. The design is compact with low noise, high phase-shift capability and also available with Ester insulation.
Interview with Stefan Klaassen, Siemens Energy’s Vice President for Power Transformers
Transformers are the important link within the energy value chain towards achieving a successful energy transition. Today, the energy landscape is changing rapidly, and our customers need to respond flexibly to power fluctuations due to renewable energy generation. Therefore, the requirements for power dissipation and continuous and reliable power transmission are higher than ever.
Our phase-shifters are an efficient and reliable way to control power flow
In an increasingly complex power generation landscape and a growing energy market, the capability to control the flow of power is crucial. Phase-shifting transformers of Siemens Energy protect lines, make grids more reliable, and reduce transmission losses. Increase the transmission capacity of your network and ensure grid stability, while minimizing expensive grid expansions with custom-designed Siemens Energy phase-shifters! They are among the most economic and cost-efficient solutions for power-flow management out there.A holistic approach: from customer challenge to energization on site
Siemens Energy has established a service that goes beyond finetuning customer requirements. Subject-matter specialists run grid studies that go toward building a comprehensive profile to answer the key question: What capabilities does the phase shifter need to solve the customer’s pain points?
Once specifications have been set, a tender can only achieve so much in ensuring a cost-efficient result. Therefore, Siemens Energy offers customers a collaborative and iterative approach to defining specifications. The experts share their insights into which combinations of specifications drive cost and performance, while the customer’s network planners have a clear picture of the required capabilities of their new transformer.
This Siemens Energy approach combines expertises to give customers a perfectly tailored transformer – the most cost-efficient and robust solution to the performance needed.
This holistic approach ensures that customer specific needs and situations affect all decisions, from the very first project stage to the energization on site. Our unique perspective produces phase-shifters, which not only are built to specs, but come with greater flexibility in addressing the customer’s challenges.
Customers benefit from…
- more than 50 years of experience in phase-shifter design
- specialist designers and phase-shifter design tools
- design rules and tools with a track record of excellent test results and highest ratings
- a multitude of options, from dual-tank solutions with “faltenbalg” to oil-oil bushings
Get the most out of your phase-shifter
As the most cost-efficient solution for power flow control, phase-shifting transformers contribute to the financial success of grid operators in a competitive energy environment. With their trademark reliability and efficiency, Siemens Energy's tailored-to-fit phase-shifters come with a wide range of competitive advantages.
- Increasing active power capacity of grid
- Allowing for direct power sourcing
- Enabling commercial trading
- Providing a cost-efficient solution for power flow control
- Optimizing losses*
- Giving operators greater leeway in planning major grid extension investments
* Depends on ratio of impedances-line resistances
Ensuring quality standards
Siemens Energy rigorously vets its suppliers. Selected partners comply with the Siemens Energy supply-chain standards, emphasizing total cost, commitment to quality, and environmental awareness.
Assembled phase-shifting transformers undergo rigorous testing at Siemens Energy's own test facilities before they are shipped to the customer. These approaches – along with Siemens signature precision in manufacturing – ensures compliance with guarantee values and a successful operation in the field.
Siemens Energy's test bays are uncommonly spacious. Why? To ensure reliable performance in their target environment, Siemens Energy engineers rigorously test fully-assembled units in their test bays – even towering giants, such as dual-tank phase shifters.
Siemens Energy's test facilities accommodate test objects of up to 35 Meters (m) in length, 18 m in width and up to 21 m in height. To give you an idea of the dimensions: This Con Edison 575 MVA - 345 kV PST comes with 19.8 m x 13.1 m x 8.9 m.
With phase-shifting transformers customers avoid expensive grid extensions
The fast-transforming energy landscape of heterogeneous power grids presents operators with similarly fast emerging challenges. In a grid struggling with unwanted power flows from adjacent networks – for example, due to the hard-to-control feed-in from renewable power plants – phase-shifters protect from additional loads and ensure grid stability and reliability by actively balancing shifting amounts of power. By changing the effective phase displacement between the input voltage and the output voltage of a transmission line as needed, phase shifters enforce, block and even revert power flows as well as reduce or eliminate loop flows. Phase shifters can rebalance line loading between parallel lines or network sections.
Standard substation transformer tap changers are used in phase shifters, as well. However, the designer has to consider the overexcitation in retard operation, that is to say, the increased voltage across RW. According to the established standard, a tap changer must be able to switch 2x the rated current. Overexcitation often necessitates limiting the overload. You can use a standard TAPCON controller.
You will need studies on Load Flow, Short Circuit, Dynamic, and Switching Transient & Protection. You may also require more specialized studies for any number of reasons, such as the particular region, in which you are located. For example, if the lines in the region are not transposed, you will need to conduct an Unbalanced Load Flow Study. Other studies may focus on the impact on harmonic power flow or subsynchronous oscillations.
