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Redundancy for Reliable Data


Renewable energy generation, although intermittent, is set to become a major contributor to the power generation system. Battery Energy Storage Systems (BESS) are getting noticed as a reliable resource to mitigate the intermittency of renewable energy and to help optimize the utilization of available resources. Plants are now growing in capacity and so are the requirements of reliable data for performance analysis and meeting compliances established by Authority Having Jurisdiction (AHJ).

Supervisory Control and Data Acquisition (SCADA) helps with coordination of various site components, to enhance the operations of renewable generation systems. Integration of SCADA systems for PV-Solar, PV-Solar+BESS, and BESS standalone plants with a power plant controller (PPC) facilitates data acquisition, monitoring, and controlling of plant performance. SCADA systems are designed to collect data from field IEDs, transfer it to a central computer facility, and display the information to the operator graphically or textually, allowing the operator to monitor or control an entire system from a central location, in real time.

A reliable SCADA and PPC communication system makes it possible to integrate protection control and reduce O&M cost. Real time acquisition and availability of reliable data facilitates intelligent decision making to improve system operation, reliability, production, and profitability. Hardware and software failure can sometimes occur during plant operations. In this scenario, redundancy of hardware and software can be a viable option for minimizing the risks of production and/or data loss, when hardware failure occurs.

SCADA system’s data acquisition and control capabilities for PV-Solar and/or BESS plants depend on the network architecture for communication with field IEDs, power plant controllers (PACs/PLCs) Remote Telemetry Units (RTUs) and off course, the SCADA platform. The reliability of a local SCADA system can be enhanced by adding redundancy for its main components like power supply, servers, and network interfaces. Using SCADA systems for renewable energy plants can use redundancy for network communications, root switches, firewalls, PPC’s, SCADA/historian servers, power supplies and HMI.


Redundancy of Network Communication: Collapsed ring topology is used for communicating with field IEDs ensuring redundancy in communication with IEDs. The collapsed ring topology enhances the redundancy of network by eliminating a single point of failure. Redundant power supplies for servers and other network devices help ensure redundancy of network communication with field IEDs.


Redundancy of Power Plant Controller (PPC): The PPC acts as the brain for regulating and controlling the output of a PV-Solar/BESS power plant, to meet the POI requirements based on the agreement between the stakeholders. All custom control logic code per the site requirements run on PPC. Depending on the site requirements, Nor-Cal Controls offers a PPC solution with the GE RX3i CPE330 for redundancy. Hot standby CPU redundancy allows a critical application or process to continue operating should a failure occur in any single component. A Hot Standby system uses two CPUs: an active unit that actively controls the process, and a backup unit that is synchronized with the active unit and can take over the process if it becomes necessary.

Redundancy of SCADA/Historian Server: Redundancy for servers can be virtualized or standalone, or a combination of both. The redundancy of SCADA system can be moved to the next level by utilizing dual servers in an active-active configuration which guarantees the continuous operation of the SCADA system. This high availability (HA) cluster which can also be combined with redundant network attached storage (NAS) for hosting redundant virtual machines in HA configuration. Nor-Cal’s network engineering team uses VMWare vSphere Essential Plus to configure this architecture and we offer the solution by request. The advantages of this configuration are high availability and fault tolerance (FT).


Redundancy of root switches, firewalls and HMI: Redundancy of root switches and firewalls are critical for maximizing the reliability of an on-site SCADA system and for ensuring an equally reliable connection of on-site system with offsite stakeholders. Nor-Cal offers a redundant Palo Alto PA-220 Firewall as a standard on all our SCADA solutions. Redundancy options for root switches and HMI is offered based on the site-specific technical specifications shared by the customer.


SCADA systems along with PPC’s act as the heart that acquires and pumps data and the brain that controls executing the logic of the PV-Solar/BESS power plant. A SCADA system helps in data acquisition from various field IEDs that helps in performance analysis of the plant. Access to quality data is critical in improving production, reliability, and ROI for the project. Effective control is critical for optimally controlling and synchronizing the resources at the site to meet the POI requirements. PV-Solar/BESS projects eligible for Investment Tax Credits (ITC) rely on quality historical data for meeting and establishing all ITC compliances.


Nor-Cal Controls has the capability to meet all the redundancy requirements to ensure success of your projects. With our core competence specializing in controls and networking, we have the ability to customize your SCADA system, power plant controller (PPC) or energy management system (EMS) requirements for your existing or upcoming projects. Get in touch with us to learn more!


Collaborators:  Jeffery Briles & Kaveh Zarei



Nashvinder Singh

Written by Nashvinder Singh

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