Visualization and control of solar power plant control systems

November 27, 2014 | Reliance SCADA

The application was developed for the needs of EnServis. It is focused on solar power plants and its main purposes are monitoring, control, and data acquisition. Since the maintenance of the plants is a priority of the company, the service technician must be informed in real time of any potential problems.

The project is divided into 3 integral parts that ensure smooth operation.

Monitoring

Monitoring is provided exclusively by ELVAC devices. They are used to compare input parameters of individual tags. The service technician is informed of any deviation from the specified limits. VBScript allows programming all monitoring mechanisms using a script. Each week, a different service technician is responsible for maintenance works. For this reason, there is a function that allows searching for a service technician depending on the week. If a service technician is unable to do his/her job, another one can be chosen from the main menu. If a failure occurs, the service technician on duty is notified via an email message.

Parts of monitoring:

• Monitoring phase voltage – in case of a phase voltage failure for a period longer than the time allowed by the Rules for Operation of Power Distribution Systems
• Monitoring the functions of current transformers (a phase voltage or current transformer failure has a direct impact on the production process because it may result in a failure in operation or in the recording of invoice values)
• Identifying the presence of low voltage – it indicates a potential problem with a plant's main switch or network protection
• The plants located close to each other monitor the production process and their service technicians are notified of any problem.
• Communication with the system is realized via Ethernet using the IEC 104 protocol. Since the data is not backed up, a failure may occur. In such a case, once the technician is verified, the scripts providing monitoring can be temporarily disabled. In addition, in the event of a data/voltage failure, redundancy of type server–server allows replacing the primary server with a secondary server.

Control

To control the plant, the service technician must be verified. This feature is not accessible to common users. The reason for that is the reduction of power production (e.g., due to service work). A script for automatically controlling the production process according to the plant's current output can be used if need be. This is, for example, due to power reduction when servicing a high-voltage transformer and replacing it with a lower-power one.

Data capture

The monitoring of the plant only at its input is insufficient with respect to possible decentralized inverter failures. Therefore, the application accesses a DB file to acquire current information on the inverters' states. In case of the reduction of power production (e.g., due to a damaged panel or a faulty fuse), the system detects the failure and informs the service technician. The notification message is sent even if an entire inverter failure or other power production problems occur.

The application is accessible via the Internet using the Reliance SCADA/HMI system's thin clients – Reliance 4 Web Client and Reliance 4 Smart Client. Reliance Smart Client is mainly used by the service technician and always allows him/her to monitor the current situation. Reliance Web Client can be used either by other members of staff or by investors to check the operation of the plant.

Examples of visualization windows

An electric power plant

Power production states at the solar power plants

A trend of a solar power plant's output

A high-voltage trend

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