Power Analysis
SPOTLIGHT
Power Analysis Projects
CALIFORNIA (CONFIDENTIAL CLIENT)
69kV Automation Warehouse Substation Ground Grid Design
Designed the ground grid for an EETS-designed 69kV substation for an undisclosed FAANG (Facebook, Apple, Amazon, Netflix, Google) company as part of a design-build
project. The design methodology adhered to IEEE Standard 80 (2013), Guide for Safety in AC Substation Grounding standards and the local electric utility requirements. The study included the following:
- Coordinating with the electric utility to gather critical information, such as fault current types, maximum clearing times, X/R ratios, and specific utility requirements, including the height of surface material above finished grade.
- Designing and analyzing multiple ground grid configurations to optimize cost while maintaining compliance with step and touch potential safety limits. This included adjustments to grid spacing, conductor size, number and size of ground rods, and surface material type and thickness.
- Accounting for site-specific constraints, such as equipment pads, the power transformer containment structure, and unique project requirements, to ensure constructability.
- Generating a detailed report for the electric utility to review and approve prior to substation construction.
ROSEVILLE, CALIFORNIA
Hewlett Packard Campus Arc Flash Analysis
EETS completed a comprehensive short circuit, time-current coordination, and arc flash analysis for Hewlett Packard’s (HP) research, development, and manufacturing facility, which spans 188 acres. The study encompassed the 12kV loop system, including buildings R2, R3, R10A, R10B, R4, Sub 5A & N/E, Sub 5C, Sub 5D, R6, and the cafe. It covered the 12kV, 480V, 240V, and 208V levels to generate PPE labels for the entire power system.
EETS conducted a one-week site visit at the HP facility to collect all necessary data, including equipment ratings and verification of field installations against the provided as-built drawings. The project also included:
- Coordinated with vendors to obtain legacy electromechanical relay curves for accurate modeling in the software used for time-current coordination analysis.
- Conducted a thorough review of the power system to identify potential code violations, safety concerns, and areas for improvement. Recommendations included corrective actions to ensure compliance with applicable codes and standards, mitigation of safety risks, and optimization of system performance and reliability.
- Electric utility coordination for customer devices coordinating with the utility.
- Providing arc flash training for HP staff across multiple locations.
BERKELEY, CALIFORNIA
EBMUD 4160V Berryman Pump Station Arc Flash Analysis
Completed a site-wide short circuit, time-current coordination, and arc flash analysis for a critical East Bay Municipal Utility District (EBMUD) 4160V powered pump station with the following features:
- Two (2) 4160V switchgear units feeding four (4) 4160V 200 HP and three (3) 4160V 400 HP pumps respectively.
- PG&E 12.47kV:4160V 2500kVA transformer.
- 1250kW, 4160V diesel generator with emergency switchover operation via 4160V vacuum circuit breakers.
- Switchgear with four (4) 4160V vacuum circuit breakers with 50/51, 50N/51N relaying.
- 45kVA 4160V:480V transformer, 480V switchboard, and auxiliary 120/208V panels.
EETS field verified all the equipment ratings and also completed the following:
- Conducted a thorough review of the power system to identify potential code violations, safety concerns, and areas for improvement. Recommendations included corrective actions to ensure compliance with applicable codes and standards, mitigation of safety risks, and optimization of system performance and reliability.
- Electric utility (PG&E) coordination for customer devices coordinating with utility.
- Analyzed all protective relaying coordination.
- Customized the study analysis and report with EBMUD’s stringent requirements
RENO, NEVADA
Apple Mills 120kV Transmission Line Sag & Tension Analysis
Completed a sag-tension analysis for the incoming 120kV line entering the new Apple Mills Substation. The design included close coordination with the local electric utility and customer to ensure compliance with design standards and proper installation requirements. For the design, EETS completed the following:
- Line Modeling: Modeled the 120kV transmission line using conductor specifications, including conductor type, size, weight, modulus of elasticity, and coefficient of thermal expansion.
- Environmental Considerations: Incorporated environmental factors such as temperature ranges, wind loading, and ice loading to simulate real-world conditions and ensure structural integrity under varying stresses.
- Stringing Charts: Generated overhead line stringing charts to provide precise tension and sag values for various loading conditions and conductor temperatures.
- Catenary Curve Profiles: Developed overhead line profiles with detailed catenary curves to visualize the line’s sag under different operating conditions.
- Pole Site Plans: Identified the power poles on a plan sheet with grading lines included.
- Vertical Clearances: Established minimum vertical clearance requirements above finished grade in accordance with CPUC General Order 95, considering factors such as terrain, roadway crossings, and proximity to structures.
- Tension Requirements: Determined pulling tension requirements and optimized installation parameters to prevent overstressing the conductor during stringing and minimize post-installation adjustments.
- Thermal Effects: Assessed thermal loading effects on sag and tension due to conductor heating during high current conditions, ensuring safe operating clearances during peak loads.
SOLANO COUNTY, CALIFORNIA
SMUD 230kV Russel Substation Wind Farm Load Flow Analysis
EETS completed a comprehensive load flow study for the SMUD Solano Wind Farm, which consists of 102.18 MW of wind turbines connected to a 21kV collection system. The system is distributed across four (4) 21kV feeder circuits extending to SMUD’s 230kV:21kV Russell Substation. This study provided an analysis of power losses, reactive power flows, and voltage support within the wind farm’s collection system and feeder circuits under various operating conditions. EETS’ key objectives and results included:
EETS completed a comprehensive load flow study for the SMUD Solano Wind Farm, which consists of 102.18 MW of wind turbines connected to a 21kV collection system. The system is distributed across four (4) 21kV feeder circuits extending to SMUD’s 230kV:21kV Russell Substation. This study provided an analysis of power losses, reactive power flows, and voltage
support within the wind farm’s collection system and feeder circuits under various operating conditions. EETS’ key objectives and results included:
- Power Loss Analysis: The study evaluated power losses within the 21kV wind farm collection system and the 21kV overhead and underground circuit segments extending to the Russell Substation.
- Reactive Power Flow Assessment: Reactive power contributions from the V-90 turbines, operating at a 0.98 leading power factor under full load, were analyzed. These contributions were critical in determining the impact of reactive power flows on system performance.
- Voltage Support and Stability: Circuit voltage support and voltage range variations were assessed under light-load and heavy-load conditions. Additional load flow models were created with V-90 turbines set to unity power factor to evaluate their effects on voltage stability.
- Parasitic Load Modeling: Inductive parasitic loads, including motors, fans, and step-up transformers, were incorporated into the study to ensure accurate modeling of reactive current flows throughout the wind farm’s collection and distribution systems.
- Operational Insights: The study provided critical data to optimize system design and operation, ensuring reliability, proper voltage levels, and minimized power losses throughout the wind farm.
Study Details:
- Feeder Circuits: The wind turbines are distributed across four (4) 21kV circuits:
- Circuit #5 serves (23) 0.66 MW V-47 turbines.
- Circuit #6 serves (9) 3.0 MW V-90 turbines.
- Circuit #7 serves (10) 3.0 MW V-90 turbines.
- Circuit #8 serves (10) 3.0 MW V-90 turbines.
- Load Flow Scenarios: The load flow was modeled in 10% increments from 10% to 100% of rated turbine output. V-47 turbines were modeled at unity power factor, while V-90 turbines maintained a constant 0.98 leading power factor at all modeled load levels.
- Voltage Analysis Models: Additional scenarios with V-90 turbines set to unity power factor at both 10% and 100% rated load were analyzed to evaluate voltage support under varying load conditions.
CALIFORNIA (CONFIDENTIAL CLIENT)
12.47kV Underground Distribution System Cable Thermal Analysis
As the digital age continues to expand, larger facilities are required to support the infrastructure needs of tech giants, which in turn demand robust power infrastructure. As part of a larger design-build project, EETS was tasked with designing the 12.47kV distribution system for an undisclosed FAANG (Facebook, Apple, Amazon, Netflix, Google) company building nearing one million square feet, powered by five (5) 12.47kV circuits.
As the digital age continues to expand, larger facilities are required to support the infrastructure needs of tech giants, which in turn demand robust power infrastructure. As part of a
larger design-build project, EETS was tasked with designing the 12.47kV distribution system for an undisclosed FAANG (Facebook, Apple, Amazon, Netflix, Google) company building nearing one million square feet, powered by five (5) 12.47kV circuits.
Given the high cost of the duct bank due to its routing around the large building, EETS conducted a cable thermal analysis to optimize its design, minimizing its size while ensuring full current supply to the building’s critical circuit loads. The study included the following:
- Coordination with the geotechnical engineer.
- Load analysis and evaluation of past similar projects of the customer to determine circuit load utilization.
- Adjustment of design parameters, such as:
- Backfill materials and thickness around conduits, while maintaining protection from heavy above-grade traffic
- Conduit types
- Cable installation depth, with a minimum of 36 inches below finished grade
- Arrangement of circuits in the duct bank based on load conditions
- Conduit spacing
The contractor later requested a reduction in conduit spacing, prompting EETS to revisit the analysis using updated parameters. The revised analysis accounted for all scenarios, given the limited margin for error. This included factoring in maximum circuit utilization, forecasted maximum temperatures over the next 50 years, and potential contractor installation errors, such as failing to maintain the designed conduit separation.