As part of an electrical generation, transmission, and distribution system, a substation houses equipment that surrounds a transformer. Specialized load testing for utilities ensures safe, efficient, and reliable delivery of electricity to consumers.
The substation’s transformer converts the high voltage power supplied by the power generating plant to lower voltages so it can be distributed to the customer. Electric power may flow through several substations between the generating plant and consumer, all at different voltage levels.
Given the complex and critical nature of this process, load testing for utilities becomes a mandatory project to safeguard performance. Throughout the facility and equipment lifecycles, you should conduct load testing for:
Regular Maintenance – Periodic load testing for utilities ensures proper operation and efficiency. Testing is critical for complex systems with multiple components, devices, firmware, and software.
Corrective Action Validation – Load testing for utilities ensures validation and verification of corrective action or system design changes. A growing trend referred to as “re-commissioning,” corrective action validation has been integrated within many utility testing plans.
Commissioning Tests – Substation commissioning involves conducting integrated systems tests before a utility goes into operation. The test ensures equipment integrates properly and performs as the facility designer intended. This critical systems test:
- Validates systems that protect the transformer, as well as other substation equipment
- Runs at the end of a project
- Tests all critical components
- Protective Relays
- Current transformers
- Voltage transformers
- Breaker equipment
- Supervisory Control and Data Acquisition (SCADA) systems
Commissioning Load Testing for Utilities
Two types of utility projects exist for integrated system load testing:
- Substation Generation Plant of 15 kV to 220 kV
- Substation for Transmission and Distribution
- Transmission – 100 kV to 700 kV
- Distribution – 12.5 kV to 100 kV
During an integrated system test at either utility project, you provide a load to ensure sensors have enough current to operate. Using a load bank instead of the utility’s load reduces project risk and improves system availability. For the best results, you should conduct the system test as closely as possible to the expected operating conditions.
Load testing for utilities requires energizing the primary substation power system. Using resistive and reactive load bank solutions emulates the power system. You can provide an accurate load to test the functionality of power substations including delivery, protection mechanisms, monitoring devices, metering, and PLC/HMI programming. Documenting the results of your testing satisfies NERC and FERC requirements.
Testing with reactive load banks demonstrates that the protective relays, monitoring, and metering systems recognize the power factor of the circuit. Understanding the circuit’s power factor ensures validation of the connections and phasing.
During load testing for utilities, a load bank creates real and reactive power flow through primary equipment. Instrument transformers transform this power to provide input to the protective relays, monitoring devices, and metering. The process confirms voltages, currents, and phase relationships. You can perform this testing within the substation without a connected incoming power line.
You and your load bank provider will calculate the reactive load bank size required to provide sufficient current for testing equipment. The calculation considers substation line voltage, current transformer ratings, and the characteristics of the relays, monitoring devices, and metering.
Key advantages of applying a reactive load:
- Tests relays monitoring current and voltage
- Validates transformer load tap changer functionality by simulating voltage steps
- Provides proper of phasing of circuits
Partnering with a Load Bank Provider for Utility Load Testing
Working with a proven load bank provider can help ensure a successful load bank testing project. It can alleviate the pressure of managing complex testing parameters and selecting the right product, voltage, and cabling for the task at hand.
With a turnkey load bank solution, you also get valuable expertise in commissioning and load testing solutions to utility scale applications. This level of support streamlines planning, logistics, and execution of your utility load testing projects.
ComRent’s team of load bank experts is ready to help ensure your system is successfully interconnected. We are offering a complimentary consultation to review your project and propose the right load bank solution for your requirements. Contact us today.