SCADA Systems Revolutionize Remote Wind Energy
Wind energy is one of the fastest-growing sources of renewable energy in the world. At the heart of this renewable evolution is Iberdrola Renewables, which is the largest provider of wind energy in the world, and the second-largest energy provider in North America. Their professionally staffed 24/7/365 energy management, scheduling and generation dispatch capabilities help Iberdrola Renewables’ customers manage risks and uncertainty in the natural gas and power industries while fulfilling energy requirements with sustainable and clean power.

The latest operation for Iberdrola Renewables is its National Control Center. In a room that looks a like NASA Mission Control, systems analysts oversee every turbine at every wind farm throughout the US. They monitor the performance and efficiency of every turbine, and they keep an eye on approaching storms to warn technicians of the danger in the field. They help the nation’s various transmission system operators insure grid reliability to help keep the lights on.

A vital element of this operation is the SCADA system. Each wind turbine has a control box containing a PLC, power converter, control boards and an I/O device at the top. Sensors for wind speed, wind direction, shaft rotation speed and numerous other factors collect and transfer data to the PLC. By detecting the wind’s direction, the control system can use a motorized yaw gear to turn the entire wind turbine in the proper direction for maximum power generation. All wind turbines are connected to a LAN, with each wind tower’s control box using Ethernet to link to the base of the tower where there is a fiber-based, redundant ring LAN connection. The LAN is connected to a remote control station running a control system that manages and collects data, adjusts turbine settings and provides intelligent alarm, troubleshooting and reporting capabilities via a central data center and control facility located in Portland, Ore.

This central control station has a SCADA system supplied by PcVue that acts as a nerve center for the wind farms. It connects the individual turbines, the substations, the meteorological stations the bird/bat aviation radar and other wildlife preservation surveillance systems to this central control room. It provides visibility for the operator to supervise the behavior of all the wind farms as a whole. By keeping a record of the activity on a time interval basis, SCADA allows the operator to determine what adjustments and corrective action, if any, need to be taken. It also records energy output, availability and error signals, and offers the capability to implement any compliance requirements and control (among other things) power factor, voltage, reactive power production, allowing for the management of wind farms’ contributions to network voltage and frequency control. It also allows operators the capability to manage power output based on real-time grid requirements.

The SCADA system communicates with the turbines via a communications network that mostly uses optical fibers. Iberdrola Renewables uses multiple turbine types and each turbine supplier provides their own control/HMI system. The major advantages of using PcVue as the main SCADA system is that it is turbine supplier agnostic and is not tied to any one PLC vendor so that it can be free to provide data reporting and analysis formats, irrespective of turbine type. This was of particular importance to Iberdrola who have wind farm operators using multiple turbines and various PLCs.

During the implementation process, Iberdrola’s team liked how PcVue was easy to configure. Its ability to iconize animated mimics and use pop-up windows reduced the risk of overlaying crucial information helped simplify the view for Iberdrola’s team. Also, the creation of templates for contents and behavior, associated with each mimic and GUI (graphical user interface) animation, ensure consistency of the window display. Iberdrola uses multi-level access rights and menus associated with each user to ensure that navigation within the application is tailored to the needs and the permissions of each individual. This allows provides a layer of security, traceability and control of users’ actions.
In the past, with a small number of wind turbines transmitting into the grid, monitoring was a relatively easy process of entry. Currently congestion has become a large issue with wind energy suppliers balancing energy production with available inputs for transmission. Requirements are quite strict, thus Iberdrola has designed an integrated system with a curtailment of setpoints in order to manage the generation profile on a real-time basis.

“We are installing wind turbines to operate in harmony with power sources such as nuclear power, solar and hydro energy in a netting arrangement to optimize performance,” said Harm Toren, head of operations services - wind, Iberdrola Renewables.

In order to manage their business, Iberdrola developed fiber optic networks on its wind farms in the US, along with its facility in Oregon. A similar system is utilized in their facilities in Toledo, Spain called CORE (Renewable Energies Operation Center). In each case, there is a central facility whereby their SCADA system is able to remotely access facilities throughout the country and access alarm and event conditions. Iberdrola’s management of multi-station configurations uses PcVue’s tools to ensure the coherence of the configuration data and deployment on all of the stations, especially for its geographically remote applications. PcVue’s centralized configuration provides the capabilities for the management and traceability of the various versions of applications and their changes. It also supports automatic updating of the stations that make up the supervisory system.

The Operation Center has the potential to supply energy service to any owner with no geographical limitations. In the US they are currently producing 3,600 megawatts of wind power over 35 independent power plants. Iberdrola maintains 2,479 wind turbines. Each wind turbine supplies about 300 to 350 data points, which equates to approximately 700,000 to 850,000 I/O data points on nearly two dozen servers. To cope with the diverse demands of maintaining Iberdrola’s wind farm, the PcVue application alarms are highly configurable. Alarm messages may be printed, viewed in alarm lists and archived. Operators configure alarm behavior using groups, filters, sorting, acknowledgement and masking. They also create alarm counters and associate specific actions with an alarm. Alarms can be acknowledged by operators directly from mimics and automatically broadcast to all nodes on the network.

Iberdrola Renewables is using OPC (and others) as the communications protocol to pull data from the various PLCs. Many wind farm applications often use OPC and the KEPServerEX driver to communicate with disparate systems. Iberdrola uses PcVue’s OPC Data Access Client and OPC DA XML Client for exchange of real time data with communication servers, and OPC DA Server to facilitate data exchange with 3rd party applications.

All of the data acquisition that occurs is routed back to the National Control Center. Toren manages the teams developing integrated control systems and the National Control Center chose PcVue’s software as they had already proven themselves to be user-friendly and highly functional in the Spanish operations.

“PcVue proved reliable, scalable and easy to configure. CORE had been kept up and running quite successfully. PcVue provides a single user view that allows an easy visual display and overall management of the myriad systems in place from PLC, HMI and the control system equipped on the turbines,” said Toren. “As we monitor aviation migration and weather in addition to controlling and managing our turbines, we needed a system that would provide a simple, easy to read GUI so that we can react at a moment’s notice.”

The PcVue SCADA software integrates and connects with the wind turbines via PcVue GUI interface acting as a light client. This configuration provides the operator with information about the turbine signals. Iberdrola is utilizing this distributed client server architecture with a redundancy to ensure the design is fault tolerant. PcVue also supports dual networks for communication with field equipment and among PcVue stations. Each component and each station in the configuration has a validity status to enable operators to view the condition of the system in real time. These client stations are communicating via OPC with the redundant communication front ends connected to the 1,000 Mbps TCP/IP Ethernet network. Each front-end is able to receive up to 60,000 I/Os.

Using the PcVue architecture, operators can see details on the data of remote wind farms in a real time. Given the large volume of information (around 350 signals per turbine), and in order to facilitate operation and maintenance of the facilities, the supervision appears in two levels.
The first level enables an overview of the most relevant alarms, values and counters, enough to supervise the turbines in a usual situation and detect failures that need to be corrected. A second, detailed supervision level, triggered on an operator’s request, enables the supervision of all the turbine’s data selected so that operators can diagnose with accuracy failures that occurred and determine the necessary operations. Data received can be processed as set points, historical storages, alarm management and trending.

The control system in each installation collects the operational information from generators and the associated substation. The system is connected to the Control Center through a remote communication channel, and facilitates maintenance tasks. The National Control Center receives this information and processes it into an organized and simplified structure that enables identification and diagnosis of failures. This diagnosis triggers the appropriate actions for its solution, remote reset or activation of local maintenance teams. As a result, average down time decreases and increases availability.

Iberdrola Renewables in the US is transitioning now for completion of the entire system by the end of 2010. So far, all expectations have been met and the system is working very well.

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