At SyncWind Power Limited, we 'Synchronise the Wind' directly into the grid.

 

SyncWind Power Limited and its engineers create quality and reliable solutions for renewable wind power and grid stability to support a cost-effective transition to the zero-emissions future.

 

The SyncWind Power Limited company-logo symbolises, that SyncWind excels at harnessing and directly 'Synchronising the Wind' into the grid.


 

 

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Grid stability with renewables? Yes, Wind can!

SyncWind.’s power-train and its synchronous generator provide physical inertia for grid stability.

 

Power grids have traditionally relied on directly grid-connected synchronous generators1) from hydro and thermal power stations contributing the synchronous attributes of system strength and physical inertia2). As renewable energy is added to modern power grids, the requirement for synchronous attributes from renewables has been brought into sharp focus. This has been highlighted by the experience in the blackouts in South Australia September 2016, Great Britain August 2019, Europe January 2021, and is an issue under discussion by grid operators and regulators internationally. 

Most countries view their fastest and easiest renewable addition to be existing asynchronous wind and solar technologies. However, over-reliance will reduce grid stability in case of any shocks to the grid. Batteries are only a partial solution as the power electronic converters (PECs) associated with asynchronous wind and solar power provide a bottleneck for the high currents required for “system strength”. It is prohibitively expensive to expand that “bottleneck”. Instead, Australian regulators and network companies have identified that dedicated synchronous generators, called synchronous condensers, provide the least-cost way to compensate for increasing amounts of asynchronous PEC renewable generation. That being the case, the cost advantages of synchronous wind turbines become compelling.

SyncWind has proven, cost-effective technology for enabling each wind turbine to drive a synchronous generator directly connected to the grid. Recently patented in a novel broad-band variable speed system, its synchronous power-train technology will scale up to multi-megawatt turbines while improving the cost and reliability advantages that have already been realised in over 1000 turbine-years of operation.

Two primary advantages that synchronous generators are uniquely able to deliver are system strength and physical inertia.

SyncWind.’s synchronous wind turbine power-train supports system strength by providing huge “short-circuit currents” (5-10 times rated) to rectify voltage faults and restore synchronism after a fault.3) It also enables FFR using the wind turbine rotor’s flywheel energy (and any reserve power that the turbine’s gearbox can support for short durations) as well as the direct generator inertia. It also provides the full range of attributes that synchronous generators provide to the grid:

  • Voltage support through a full range of reactive power capabilities.

  • Synchronous condenser mode even with no wind.4)

  • Controllable power level and ramp rates.

Physical inertia instantly resists speed changes in a grid shock, such as the failure of a large power plant or a transmission line. Generator speed determines grid frequency, and vice versa for all the generators on a synchronous grid. The larger the shock or the lower the inertia, the faster the rate of change of frequency. Therefore, grids need inertia for stability.

What does physical inertia2) do? 

It enables grid frequency to be stable.  Any device or system with physical inertia has the momentum to “ride through the bumps”, without slackening speed.  By contrast, controlling a system with little inertia involves working very fast with the “gas pedal” to alternatively squirt in more power, or reduce the amount squirted in, depending on whether the system has slowed down or sped up.  In an electricity system, inertia normally comes from synchronous generators, which inherently (through electro-magnetic reaction) combine their physical inertia in an instantaneously co-ordinated way, even when hundreds of kilometres apart.  But most wind turbines’ generators are not synchronous like this. They have zero inertia because their spinning masses are decoupled electronically from the grid.

So, the increase of renewable energy is causing system inertia to reduce.  With a low inertia electricity system, multiple generators would have to “work the gas pedal” in an instantaneously co-ordinated way, to maintain a steady frequency. This is unproven with current PEC wind turbine technology. With zero inertia connected to the grid and widespread geographic distribution , they have a good chance of undershooting, overshooting, or getting out of rhythm and losing control, causing blackouts.

While asynchronous wind turbines can in principle provide Fast Frequency Response “FFR” (sometimes referred to as "synthetic inertia", see inertia2) below) to respond to grid shocks via their power electronics, this relies on a mixture of power stored in the flywheel energy of the wind turbine and any ability to increase output power (for example if the turbine is running significantly derated). Solar panels are less able to provide FFR due to the lack of a spinning mass and can only provide it if they are running significantly derated or in conjunction with expensive batteries.

SyncWind.s power-train enables a synchronous generator to be directly connected to the grid, providing inertia for grid stability the same as traditional power generators, without power electronics. This delivers direct resistance to frequency change as opposed to providing only FFR, which, equally, the SyncWind.’s system will also be able to offer.

SyncWind.’s system has been IEC certified by Lloyds Register and has a track-record of more than 1000 turbine-years of synchronous wind power operation.  The cost-effectiveness and track record of SyncWind.’s system differentiate it from a small number of other synchronous wind turbine systems that have been tried.

SyncWindi welcomes the Media Release: Blueprint for a world-class electricity system, 09 June 2017 by the Australian Government’s Chief Scientist, Dr. Alan Finkel, of his final report Independent Review into the Future Security of the National Electricity Market - Blueprint for the Future recommending a range of changes to the Australian electricity market to improve system security.  These Recommendations include requirements for minimum amounts of inertia and all of the above attributes that synchronous generators have traditionally provided, and SyncWind.’s system provides within the wind industry.

SyncWind.’s system has recently been extended with a new patented system to enable broad-band variable-speed operation which wind turbines require in lower wind climates.  SyncWind Director Geoff Henderson stated “Our patent protected technology, which is scalable to both the mid-size and multi-MW turbine market, eliminates use of power electronics and results in significant noise, weight and cost reductions. Further, and as evidenced by demand for renewable energy to assist grid stability, SyncWind.’s proven designs and technology are an idea whose time has come”.

A cursory examination of the issue of grid stability in the renewable transition makes it abundantly clear that there is increasing market concern about this issue. Difficulties are now beginning to be apparent in China, Europe, Texas, Australia and remote communities like the Pacific Islands which are investing heavily in renewables including solar. As the world moves to renewable energy in the next few decades, it will become an issue for all nations.
 

SyncWind.’s solution was awarded the Efficient Solution Label by the Solar Impulse Foundation, Switzerland, of which SyncWind is a member.

SyncWindi is actively seeking partnerships with stakeholders who are at the forefront of wind energy and interested to commercialise SyncWind.’s proven power-train technology. Please see the Executive Flyer.

In addition, please see the paper "Field Experience with Synchronous Wind Turbines in New Zealand and Scotland" by Geoff Henderson, presented at the “16th International Workshop on Large-Scale Integration of Wind Power” 25 - 27 October 2017 in Berlin (http://WindIntegrationWorkshop.org).

SyncWindi is also pleased to communicate directly with grid operators, consultants, academics, journalists and other parties interested in issues in grid stability. 

We are seeking investors for our various technologies, especially for our patented power-train for multi-megawatt (or mid-size) wind turbines. Please contact us for further information.

Author: Geoff Henderson - Date: 17.5.2021

 

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1)   Synchronous generator:   The term “synchronous generator” in this article refers to synchronous generators which are directly connected to the grid (i.e. hydro and thermal plants as well as turbines with SyncWind.’s system). Please note, that a few competitors’ wind turbines use synchronous generators, which are connected to the grid via power electronic converters/inverters (PEC), and therefore cannot provide physical inertia to stabilize the grid.
      In other publications, the terms “synchronous machines” or “synchronous turbines” might be used instead of the term “synchronous generators”. 

 

 

 

2)   Inertia:   The term “inertia” in this article refers to “physical inertia”, which is the inertia provided by the spinning mass of generators, which are directly connected to the grid, and therefore inherently help to stabilize the grid (i.e. hydro and thermal plants as well as turbines with SyncWind.’s system).  Most competitor’s wind turbines use generators, which are connected to the grid via power electronic converters/inverters (PEC) and do not provide physical inertia.
      Inertia should not be confused with “synthetic inertia” which is fundamentally different, being a form of fast frequency response (FFR), which is essentially a governor response (involving measure and control steps which take time) rather than an inertial reaction that slows the rate of change of frequency, providing time for a governor response to stabilize the grid.
      “Physical inertia from synchronous machines plays an important role in slowing the rate of change of frequency when there is a mismatch between supply and demand, allowing time for frequency control mechanisms to respond.”  (Australian Chief Scientist, Dr. Alan Finkel, Independent Review into the Future Security of the National Electricity Market - Blueprint for the Future
, June 2017)
      In other publications, the terms “mechanical inertia”, “rotational inertia” or “synchronous inertia” might be used instead of the term “physical inertia”.

 

 

 

3)   SyncWind.s system strength:   In comparison to the ability of SyncWind.’s system to provide huge “short-circuit currents” (5-10 times rated) during faults, other wind turbines with power electronic converters/inverters (PEC) may provide “short-circuit currents” of only about up to 1.3 times rated, due to the current (amperage) limitations of transistors.
      In other publications, the terms “fault current” might be used instead of the term “short-circuit current”.

 

 

 

4)   SyncWind.s synchronous condenser mode:   SyncWind.’s synchronous condenser mode provided reactive power which generated up to 1/3 of the revenue generated by the first Windflow™ 500 turbine in New Zealand (due to incentives offered in 2003 for reactive power by the network operator). SyncWind.’s synchronous wind turbine can also import reactive power to reduce line voltage, as in 2006/2007, when 5 turbines imported kVArs up to 130% of the turbine rating at the Te Rere Hau wind farm to control voltage on an 11 kV line  (Field Experience with Synchronous Wind Turbines in New Zealand and Scotland , Windflow Technology Limited, Geoff Henderson, 27.10.2017, Berlin).

 

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Last modified: 08.08.2021