| Transmission & distribution
Distinguishing it from legacy SSSCs, SmartValve is transformerless and uses an integrated, fast-acting bypass for protection from system faults, Smart Wires notes. A SmartValve installation is connected in series with a utility facility, operates at line potential and has no connection to ground.
SmartValve basics
Power flow on a line depends on the line’s voltage and current. The voltage of a given line remains close to constant, so the best way to change the amount of power a line is carrying is to change the line current. This can be achieved by changing the impedance of a line (volts = current x impedance). Impedance is a combination of resistance and reactance, and SmartValve impacts the reactance of a line. It senses the line current and injects a leading or lagging voltage waveform in quadrature with the line current, which has the effect of changing the line’s reactance. This means it can increase or decrease power flows in the line circuit and perform dynamic services.
In recent years, the global energy landscape has changed profoundly, says Smart Wires. Today’s utilities face challenges far more difficult than those encountered in previous decades – integrating more renewables, increasing flexibility and stability, and improving inter-regional power transfers, while reducing constraints, costs, and environmental and community impact. But the grid was designed for large, central power generation, not large scale, intermittent and distributed renewable generation. Energy generation and demand patterns are shifting markedly.
“This is where Smart Wires comes in”, the company says. “We partner with electric utilities across the globe, helping them to solve their biggest challenges, achieve their strategic objectives, and evolve their grids with flexible, high-impact solutions.”
As distinct from legacy forms of power flow control, says Smart Wires, SmartValve “is a modular, digital solution which means it is
Above: FARCROSS/IPTO SmartValve installation in Greece
quick and flexible to install and easy to scale or relocate. This flexibility and adaptability is incredibly valuable when generation, load, and the evolution of the grid itself are highly uncertain.”
A recent Brattle Group report, referenced by Smart Wires, found grid enhancing technologies could double the renewable generators able to connect to the grid over the next five years compared with “the status quo approach to transmission planning.”
Smart Wires, headquartered in North Carolina, with European headquarters in Dublin, was listed on the Nasdaq First North Growth Exchange, Stockholm, in May 2021, with the ticker symbol, GoGrid. The company currently has a workforce of around 150.
Its vision is a transition to a digital grid based on “silicon and software”, as opposed to the “copper and steel” of today’s grid. Smart Wires traces its power flow control concept to around 1998 and the ground- breaking work on FACTS done at that time by Westinghouse’s Power Electronics group and
the Electric Power Research Institute (EPRI), introducing power-electronics-only technology to transmission systems for the first time. “This was widely acknowledged as a breakthrough for variable power flow control on the grid and the definitive door-opener for Smart Wires’ future innovations”’ the company says.
Motivated by the 2003 Northeast Blackout, Georgia Tech developed a smart power flow control concept that became an early version of the first-generation (magnetics based) PowerLine Guardian (an antecedent of SmartValve (silicon based)).
“A partnership of some of the largest and most-respected utilities converged around this idea and launched Smart Wires. They saw the concept’s potential for meeting a critical need – flexibility – given the rapid changes occurring on the grid”, the company says.
According to Smart Wires, SmartValve “offers 600 times the impact – at 5% of the cost – compared with the first-generation product.” The company says it “has spent the last decade becoming a proven solution.”
Above: Before SmartValve
After the loss of one line, unequal loading on the remaining lines limits network utilization to 40%. Although the thermal capacity is 3000 MW, the maximum usable capacity is restricted to 1200 MW.
Above: After SmartValve
Power is PUSHED & PULLED to lines with spare capacity. By balancing flows, transfer capacity is increased to 3000 MW even after accounting for the loss of any one line. Maximum utilisation is achieved by small applications on multiple circuits
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