Production Balance Management in a Virtual Power Plant Environment System Overview
Overview The Production Balance Management system consists of different modules, which the customer freely can assemble to an individual working system. The Production Balance Management system is designed to support the different tasks that are necessary for the daily planning of power production. Production Balance Management modules overview 2
There are modules included for importing, processing and exporting data. Import to and export from the system can be done by various protocols, like FTP, Mail, Web services etc. Furthermore the customer can integrate their own modules and protocols in the system. All data is saved on an internal database, which can be a Microsoft SQL Server, Oracle or MySQL type of database. In addition most incoming data like weather data, price data and activations from outside are saved on the system server s hard disk so is most outgoing data. Normally regular power production is planned one day in advance. The individual power plants may have their own strategy of planning power production schedules and bids or they might want the system to automatically calculate these data. During the day, the power schedule and the current real power production are constantly monitored. In case of any significant imbalance the Production Balance Management system tries to compensate incorrect production by activating the power plants or units reserve plan. The system finds the best fitting power plant or unit that can solve the problem at the lowest price. The solution even takes the advantages of green and sustainable energy into account. The Production Balance Management system contains various applications and tools that can display and report the current state of the system. Although the system is designed to operate mostly automatically, the user can intervene and take full or partial control over the operations of the production. If a power plant has its own planning strategy, the plant would actively transfer its calculated data to the main data center at the Production Balance Management. However it is also a possibility to place this responsibility at the Production Balance Management system. In the latter case the Production Balance Management system has to have access to detailed information about the power plant, its units and the physical and economic characteristics. 3
Predefined Subsystems The modules of the Production Balance Management system can be combined in various ways in order to build quite different types of applications and subsystems. Picture 2 shows some of the possible configurations, but others are conceivable too. production and the production schedule, the Balance Manager tries to compensate for the incorrect production by activating the power plants or units reserve plan. The system finds the best fitting power plant or unit that can solve the problem at the lowest possible price. The solution even factors in the advantages of green and sustainable energy. If compensation of the imbalance is not possible a newly generated production schedule is sent to the TSO to indicate and signal the problem. Production Balance Management subsystems overview To build an individual system, the necessary modules have to be selected and combined. If parts of different predefined subsystem are needed, only the corresponding modules have to be added to the system - not the entire subsystem. In this way there is no need to purchase multiple different systems when only specific parts of each system is needed. BM Balance Manager All subsystems in the Production Balance Management system can be equipped with a Balance Manager (BM). Each power plant or unit can transfer a reserve plan, which can contain positive and negative values and which indicates effects that can be activated if necessary. The Balance Manager constantly monitors the balance between the production schedule and the real power production. In case of a significant imbalance between the actual 4
VPP Virtual Power Plant The VPP is a system designed to combine power plants of different types, sizes and economic characteristics. The main goal is to achieve the greatest possible profit and in the same time maintain the balance of power production. On the outside the VPP acts as a single power production plant, which publishes one single power production schedule and which can be regulated by one single activation plan. Even other VPP systems can be added, which makes the system scalable. If the original production schedules have to be corrected, the recalculation takes the individual characteristic of each power plant, unit or subsystem into account and optimizes both on the power production and the security of heat supply. On the inside however, the VPP combines many different types of power plants or production units as shown in picture 3. Each individual power plant or unit is independent of the others and can do its own planning of scheduled power production and bidding. The VPP works perfectly with single physical power plants like conventional power plants, combined heat and power plants, water power generators, biomass power plants and electric boilers. Wind turbine farms and sun power farms are integrated as single producers and are controlled automatically by One View Energy Control Unit from SCADA International. Individual power plants that are planned automatically by a PPC system can also be integrated into the VPP. It is possible to add more than one PPC. Plant types in the Virtual Power Plant 5
OneView Energy Control Unit from SCADA International provides solutions for: Interfacing to different first level SCADA systems Interfacing to Cap banks (option) Interfacing to Grid measurement equipment Interfacing to Utility Data logging SCADA OneView Reporting on logged data (Lost production) Presentation of data Regulation of sub wind parks - Active power control - Reactive power control /Cos/ (Optional voltage control) - Frequency control OneView Energy Control Unit 6
PBC Production Balance Center PBC is a production balance control system that applies to companies with production balance responsibility. It is an interface layer between the different power producers, the TSO and the power exchange. Production schedules can be imported from various sources and exported to the TSO and the power exchange. All schedules can be monitored. The balance between production schedule and real production is also monitored and alarms are triggered in case of imbalance. Typical power production sources are: Conventional power plants and combined heat and power plants Wind turbine farms Sun power farms Water power generators Biomass power plants Electric boilers Any other power plant PBC monitors production schedules, online production values and imbalance 7
Market bids can be imported from various sources and exported to the TSO and the power exchange. The PBC system contains modules to display and monitor the power plants market bids and the corresponding bid activations. The system receives bid activations from the TSO or the power exchange and automatically sends them to the corresponding power producer. As all subsystems of the Production Balance Management system, the Production Balance Center can be equipped with a Balance Manager (BM) for automated compensation of imbalance. PBC monitors market bids and bid activations 8
PPC Production Planning Center PPC is a production planning system primarily directed towards the needs of companies that are responsible for power production. The system performs fully automated calculations of the registered plants optimal production schedule, sends these schedules to the balance responsible party and distributes the plants current approved schedule to the plants units for direct start-stop of these units. Each power plant or unit that is registered in the PPC acts as an individual and independent power producer. Each has its own optimized schedule and bids. The PPC system contains a user interface with a detailed overview of the condition of the system. One row of information is shown for each plant configured in the PPC system. The system shows one column for each possible activity that can be carried out. The cells indicate whether the activity has been carried out, and whether it has been carried out correctly or not. Where the activity of distributing production schedules is shown, the actual effect in the production is also shown. Additional information, like error messages, is shown when the pointer is placed over a cell. PPC overview The units of a production plant are only to be started in periods where the price for the delivered amount of power is the highest and the revenue thereby the largest. Furthermore, the units cannot be started if the accumulation tank has reached maximum capacity. The calculation of the plants optimal run is divided in the following modules: Optimal production schedule Gathering weather observations, weather forecasts, spot price forecasts and availability forecasts (typically seven days ahead). Gathering observations of heat consump tions and the contents of the accumulation tank for each plant. Calculating the plant s expected heat con sumption for the following days. The system uses artificial intelligence that automatically learns the correlation between weather data and heat data, based on historical observations. Calculating the plants optimized produc tion schedule. The calculation is based on the registered price forecasts and the cal- 9
culated heat consumption data. The plants can resign their units per hour. The optimization calculates with zero production in these periods. Forwarding the plant s production schedule to the production responsible party s balance system. Actual production schedule The module s primary task is to distribute the plants current approved production schedule to the production units of the plants. The production schedules are retrieved in regular intervals from the Production Responsible Party s balance system. Production schedules for the units of the plant are made from the current production schedule, available in 5-minute intervals. The PPC system contains a web application module, which can be used to interact with PPC. As all subsystems of the Production Balance Management system, PPC can be equipped with a Balance Manager (BM) for automated compensation of imbalance. PPC web application Planning a day ahead The Production Balance Management system can automatically calculate optimized power production schedules and market bids for the registered power plants, through modules like Production Planning Center (PPC). In this case the system has to have access to detailed information about the power plants and units physical and economic characteristics. For combined heat and power plants a heat consumption forecast has to be made in order to calculate production schedules and market bids. In order to calculate the heat consumption forecast, the following information must be available about the power plant: 10
Heat consumption: Historical and current heat consumption Weather observations: Historical and current weather observations Weather forecasts: Current weather forecasts for the next days For each unit of the power plant the following information must be available: Type: The type of unit. Power production value: How much electricity can be produced. Heat production value: How much heat can be produced. Cost: The cost of power and heat production. Gradients: Start and stop gradients. Minimum production plan: A time series with a one-hour interval that indicates the minimal possible power production value. The values can be different from 0 to force operation of the unit. Max production plan: A time series with a one-hour interval that indicates the maximal possible power production value. The values can be set to the corresponding minimal value to signal that the unit will be offline. After the calculation of production schedules and market bids have been made, these data are reported to the corresponding companies like the TSO or a Balance Responsible Party. 3.2. Monitoring Intra Day The Production Balance Management system can be set up to monitor production schedules continuously. In case of a significant imbalance, alarms can be sent by mail or to other destinations. Furthermore the Production Balance Management system can be set up to recalculate the power plants production schedule to find the best fitting unit that can solve the problem at the lowest price. Newly calculated production schedules are reported in the same way as the original production schedules which were generated one day in advance. 3.3. Distributing Power Production Schedules Production schedules are normally sent to the TSO or a Balance Responsible Party, were they are acknowledged. After acknowledgment, the approved production schedules are sent back to the power plants and units. Some power plants have to act on the acknowledgement manually, like the ones that perform planning manually. Others can get the individual units started automatically via modules like the PPC or the One View ECU. Furthermore the following data must be available: Price forecasts: Forecasts for the spot price and other market prices for the next days. Wind farms and solar plants are treated in a special way. These power plants will be set up with one single unit each, because the One View Energy Control Unit from SCADA International already dispatches a single production schedule to the different contained units. 11
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