Transmission & distribution |
STATCOM-plus-storage for grid stability
SVC Light® With its new offering, SVC Light® Enhanced:
Enhanced, Hitachi Energy (formerly Hitachi ABB Power Grids) combines two grid stabilisation technologies, STATCOM and energy storage (supercapacitor-based), to provide both active and reactive power to transmission systems
MACH™ control system
SVC Light®
Control algorithms & system expertise
Reactive power
SVC Light Enhanced – the basic idea
SVC Light® Enhanced
Super- capacitors
Active power
Through advanced control capabilities using grid-forming control, SVC Light Enhanced aims to dynamically address the problem of declining grid inertia levels combined with increasing demands from grid users for improved power quality. SVC Light Enhanced builds on the flexibility and modularity of Hitachi Energy’s SVC Light STATCOM, a well established technology for providing efficient reactive power compensation. The active power capability is provided through the addition of a supercapacitor system, which is integrated with the SVC Light STATCOM technology.
Building blocks of SVC Light Enhanced The active and
reactive power flow is controlled via advanced algorithms within the MACH™ control system, allowing “grid operators and utilities to dynamically adapt
Active power Reactive power
Multiple services provided by SVC Light Enhanced – contributing to future grid stability
Power system
Grid-stabilising services
Voltage regulation Inertia
Short-circuit contribution Flexibility/modularity Controllability
Voltage regulation: the same dynamic voltage regulation capability as SVC Light, through the controlled injection or absorption of MVAr
Inertia: the addition of supercapacitors adds active power capability to support the grid with fully controllable inertial response in a matter of milliseconds
Short circuit contribution: SVC Light can inject current during short-circuit
Flexibility/modularity: SVC Light Enhanced provides system strength support by limiting the consequences of power system events
Controllability: the grid-forming capabilities of the MACH control system make SVC Light Enhanced adaptable to rapid evolving grid conditions
the transmission system to the new energy and load mix”, says Hitachi Energy.
What Hitachi Energy describes as an “all-in-one solution for future grid stability” draws on “design and life-cycle knowledge from over 50 years of experience and over 500 installations in the field of dynamic reactive power compensation”, the company notes, putting Hitachi Energy “in the unique position to develop a system capable of delivering hundreds of megawatts in a single installation”, it says.
01 02
With such a “meaningful amount of energy storage available”, SVC Light Enhanced is able to provide “highly demanded and valuable services such as inertia, short circuit contribution, and system strength support, in addition to the voltage regulation capability of traditional STATCOMs.”
03 04
01 Converter valve: the converter valve utilises Multi-Level Modular Converter (MMC) technology, employing high-power semiconductors, to control the exchange of active and reactive power with the power system
02 Cooling system: the cooling system consists of a closed-loop, deionised-water circuit to cool the converter valve and provide a compact converter design with high current handling capability
03 Control system: the MACH™ control system acts as the brain of SVC Light®
Enhanced using state-of-the-art computers, micro-controllers and digital signal processors
04 Energy storage: racks of supercapacitor modules, series and parallel connected, provide the active power capability of SVC Light®
Enhanced
For a given grid event, this graph demonstrates the increasing impact on Rate of Change of Frequency (ROCOF) as levels of power system inertia (Hsys) decrease
50.2 50.0 49.8 49.6 49.4 49.2 49.0
0
Hsys = 36 s Hsys = 21 s Hsys = 16 s Hsys = 11 s
Historically, large generators with their heavy rotating masses, have provided vital services to the grid such as voltage and frequency stability. The accelerating transition to renewables has the side-effect of reducing inertia in the grid, making frequency more sensitive to power fluctuation events, which in turn jeopardises frequency stability.
SVC Light Enhanced aims to address these inertia shortage and frequency instability challenges.
With power networks evolving rapidly, Hitachi Energy emphasises the grid-forming capabilities of SVC Light Enhanced and its flexibility to adapt to changing grid conditions.
With ever-more non-linear electronic loads, grid operators will encounter higher and higher harmonic levels in the power system, says Hitachi Energy.
By incorporating advanced control functionalities such as grid forming, SVC Light Enhanced “has the capability to operate safely even in harmonic-rich environments”, the company points out.
ROCOF 5 Time, s 10 15
It also notes that interaction between grid devices is a growing challenge to system safety and stability. The SVC Light Enhanced controls are designed for “passivity to resist interaction with other grid facilities, especially under sensitive frequency ranges, behaving as a robust machine” and “the use of grid-forming control capability provides stable operation in weak grids and reduction of voltage imbalances.”
22 | October 2021 |
www.modernpowersystems.com
Traditional STATCOM
Synchronous condenser
SVC Light® Enhanced
Frequency, Hz
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