DER Interconnection and Power Systems Studies

Alberta utilities face increasing demand for reliable, resilient, and sustainable power delivery in their service areas. To address these challenges, utilities are deploying Distributed Energy Resources (DERs) to enhance grid stability, reduce transmission losses, and support localized generation closer to where power is consumed. By integrating DER sites, electrical utilities can improve voltage regulation, defer costly infrastructure upgrades, and enable greater flexibility in balancing supply and demand.

For these DER sites to be effective, they must meet CEC, IEEE and Utility Interconnection requirements and effectively integrate with utility distribution networks. This requires precise system coordination to isolate faults and protect utility customers. Each site must incorporate arc flash mitigation measures to safeguard personnel and include automated control and synchronization capabilities to generate power and provide system stability when required.

To meet the above requirements, Delta Wye Engineering was hired to:

1. complete a thorough power system study (Load Flow, Short Circuit, Protection Coordination, and Arc flash)
2. Provide technical expertise for site coordination and utility interconnection requirements.
3. Perform all protection calculations and protective relay programming for the system.
4. Support testing and commissioning

Delta Wye Engineering performed detailed site modeling to accurately represent 5 DER power systems. The models were analyzed through:

• short-circuit, 
• load flow, 
• coordination, 
• and arc flash studies 

to verify safe operating conditions and ensure compliance with electrical utility interconnection standards. 

Once a baseline was established, the model data and utility requirements were used to develop relay programming setting files designed to minimize arc flash hazards and implement an effective protection and control scheme. 

The results of each site were summarized within their own report and provided to the client with SEL relay settings files. 

Delta Wye then continued to provide commissioning support during on-site troubleshooting performed by our client.

Delta Wye collaborated with our client to refine relay settings, implement utility interconnection requirements, integrate with plant automation, and provide comprehensive support during testing and commissioning for each site. Additionally, Delta Wye provided remote support during the troubleshooting of phasing, voltage stability, and generator start-up challenges. Our staff were available by email and calls to promptly address any questions or concerns found by other on-site teams.

Our project communication was minimalist and efficient. We exchanged emails and phone calls. This was a sufficient plan for this project, and removed time-consuming meetings and routine (weekly/bi-weekly) project burdens that ultimately helped deliver the project under budget. The routine nature of this work for us, plus the effective support of our client, resulted in an efficient relationship and project.

Capabilities demonstrated

• Power system modeling 
• Load Flow Studies
• Short Circuit Studies
• Coordination Studies
• Arc flash studies
• Power System Studies
• Protective relay calculations and relay settings
• Relay programming including logic programming, settings, communications, event reporting, and SCADA integration.
• Utility interconnection compliance and approval support.
• Remote testing and commissioning support and troubleshooting
• Power System Industry knowledge in:
  • Generation
  • Protection & Control
  • 25kV, 4.16kV, and 600V systems
  • Utility Interconnections

Engineering Tools Used

• EasyPower Software
• AccSELerator Quickset
• Delta Wye Protection Calculation Sheets
• Delta Wye Quality Checklists
• Utility Interconnection Standards

Equipment Involved

• Natural Gas Generators
• 25kV and 5kV switchgear
• LV MCCs
• Power Transformers
• Zig Zag Transformers
• Uninterruptible Power Supplies
• SEL 751 relays
• SEL 700G relays
• SEL 787 relay

Standards Leveraged

• IEEE 1547
• IEEE 1584 
• CSA C22.1 (CEC)
• CSA Z462
• IEEE 3000 Standards Series