In fact, these demands apply to operators of conventional power plants as well, who now require efficient load flexibility in order to deal with fluctuating and intermittent supplies from renewable energy plants, such as wind farms and solar power plants, to the national power grids. The ability to respond quickly and cost-effectively to rapidly changing load requirements is now crucial for power generators.
The new generation of control systems must achieve total plant automation by providing a system platform that increases energy efficiency, improves engineering productivity, and supports more effective, flexible and reliable plant operation with an enhanced energy and maintenance management strategy. The remote monitoring of process information in real-time is an important prerequisite for economical and operational stability.
Grid codes
Electricity generators are legally obliged to comply with stringent network code requirements particular to each country of operation. Also known as ‘grid codes,’ they specify the technical conditions and processes required for generator compliance with all aspectsof planning, connection and operation.
The essential grid code factor is the requirement to ensure renewable plant control is designed so the plant can provide similar grid support functions as conventional power plants.
Symphony Plus for Renewables addresses these requirements with its newly developed hardware platform (SD I/O) and controller (SPC700), which provides the necessary computational power and communication protocols to ensure proper monitoring and control of the plant. Dedicated control logics for wind and solar installations ensure plant compliance with grid codes, while maximizing power production at all times. Active power and reactive power control, steady-state voltage and power factor are some of the key control logics integrated into Symphony Plus.
Beyond grid codes
Symphony Plus for Renewables has been uniquely developed to integrate generation and electrical infrastructures (substation, capacitor banks, STATCOMs, etc.) into a single monitoring and control system for the power plant. The integration of the process power plant and the substation automation systems results in higher levels of availability, operator visibility and operational reliability.
Using standard protocols, such as IEC 61850, Modbus TCP and IEC 104, the number of control systems across a plant and the complexities associated with the engineering, installation and commissioning of individual control systems are both reduced. Information can be seamlessly distributed to control operators, maintenance engineers and plant engineers via a common database management system.
Having all assets integrated into a single control system is essential to the optimization of wind power plant production.
Optimization of plant production
Continuously monitoring both the individual output of each wind turbine asset and the cumulative output of the wind farm involves collecting large amounts of operating data, like wind speed/direction, rotor speed, and interpreting this in line with production data, such as active/reactive power. This data supports decisions to ensure each turbine as well as the farm as a whole are operating effectively and at optimal efficiency, and enables modulating the output of the turbines to meet the required loads.
‘Wake effects’ can account for several percent of a wind farm’s total power losses, depending on layout, compared with non-wake, free-stream wind conditions. To maximize power production and revenues by overcoming the wake effect, Symphony Plus studies the aerodynamic interaction between turbines. A powerful online optimization engine also boosts the active power of each turbine to maximize power production of the entire plant, while reactive power control minimizes overall losses in the collector grid.
The remote monitoring capabilities of modern automation systems present both individual plant operators and those managing power plant portfolios with a high level of plant operating visibility. Remote systems provide dynamic decision-making tools to help operators optimize plant availability, detect any abnormal functionality and ensure that energy efficiencies are being maintained. The benefits from improved operation and maintenance regimes and reduced operating expenditure improve business profitability.
Symphony Plus remote diagnostics is a key functionality that calculates and forecasts the condition of assets based on overall working conditions during their lifetime. This provides greater awareness of plant conditions, and dramatically improves the maintenance process and its effectiveness. Condition-based maintenance, or predictive maintenance, minimizes costs associated with asset maintenance, and drives down the overall levelized cost of renewable energy.
Owners or operators of large numbers of solar and wind power generators increasingly need to create virtual power plants (VPPs). Centralized remote monitoring of VPPs enables energy production from geographically remote power plants to be accumulated and aggregated. This facilitates participation in the power purchase market, improved load balancing and optimization of on-site electrical production and consumption.
Symphony Plus remote monitoring, integration of forecasting and portfolio-wide power management ensures optimal operation of VPPs via the backbone of a central control and optimization system. This system connects decentralized assets, and provides real-time optimization of operations and planning.
Scalability, redundancy and high availability are crucial features of Symphony Plus that comply with the needs for extension of VPP operators. Realtime calculations and flawless response times via communication channels are key proprieties of Symphony Plus that support renewable energy trading in various markets, including the ancillary service market.
The key function that makes Symphony Plus a stand out control automation solution is its capacity to optimize dynamically, in real-time and intraday, the running costs of an entire portfolio of plants. It uses a mathematical optimization program to distribute overall schedules to individual units, taking all current restrictions and disturbances into account. Moreover, the instantaneously incoming balancing power calls
are converged with individual schedules to provide the optimal set-points for all technical units.