Case Study
Switchgear Replacement Study and Implementation
Challenge:
The units and switchgear for our client’s power plant had been in service for over 60 years, were nearing their end of life and presenting reliability concerns. Our client wanted to install upgrades to the 4kV switchgear and needed to know all of their options to get the project approved and funded.
Solution:
Three options were investigated and analyzed, with the following goals in mind:
- Upgrade switchgear, preferably without replacing switchgear by uprating and component replacement
- Add excitation – 2 additional breakers
- Reuse as many cables as possible
- Lower arc flash values to 8 cal/cm2
- Utilize more capacity from existing 20 MVA transformers, 2780 A available, uprate to 2500A main and bus, 3000A preferred
- Uprate non-segregated phase bus to at least 2500A, 3000A preferred.
- Upgrade relaying, replace existing fault bus scheme with more modern protection scheme
- Consider replacing feeder breakers with contactors
- Remote racking
Valdes prepared specifications for switchgear and related hardware. The packages were issued for budgetary bids and cost estimates were prepared for two of the options. Valdes submitted a report with the results to client for review and final for internal use in obtaining project approval and funding.
To support the estimates, Valdes also provided the following documents:
- Revised single line diagram and typical three line diagrams
- Conceptual general arrangement of switchgear and typical switchgear door layouts
- Spec for switchgear replacement breakers and bus rerating to obtain quotes
- Spec for switchgear replacement doors with new relays to obtain quotes
- Cost estimate (+/- 10%) for the total project itemizing engineering, equipment, construction, commissioning costs, and spare parts
- Project schedule including time for detailed engineering, procurement, pre-outage work, construction, and commissioning.
Impact:
The study results were used by the client to approve funding for switchgear upgrades on five additional units. Valdes was awarded the detailed engineering to complete this project on the remainder of the units at this facility, as well as associated upgrades at our client’s other generating stations.
SERVICES:
Electrical
- System Analysis (SKM Power* Tools):
- Load Flow
- Short Circuit
- Overcurrent Coordination
- Arc Flash
- Transient Stability
- Utility/Industrial & Transmission/Service Substations
- Industrial Power Distribution:
- Power Transformers
- Low/Medium Voltage Switchgear
- Motor Control Centers
- VFD Installations
- Protective Relay Settings, Generators & Distribution
- Diesel Generator and UPS Systems
- DC systems
- Grounding & Lightning Protection
- Lighting
- Equipment & Raceway Layout Drawings
- Wiring Diagrams & Schematics
- Electrical Heat Tracing
- Area Classification & Code Compliance
Instrumentation & Controls
- PID Controller Application & Specification
- Instrument Selection & Specification
- Instrument Index & I/O Lists
- Control Valve Sizing & Specification
- Instrument Loop & Interconnection Diagrams
- Smart Plant Instrumentation/INtools
- HAZOP Participation
- Control Panel Design Instrument Location Plans
- Installation Details
- Instrument Commissioning
- Safety Instrumented Systems (SIS) Implementation*
- Engineering & Design in Accordance with ISA84 & IEC-61511 Standards
- HMI, MMI, & SCADA Functional Specifications
- Operator Interface Specifications
- Operator Usability Studies
- PLC & DCS
- Specification Selection
- Functional Descriptions
- Ladder Logic
- Hardware Interface
- System Architecture Drawings
- HART & Foundation Fieldbus
- Control Room Layout & Design
- Control System Training Manual
- Site/Factory Acceptance Testing
Cost Estimating
- Develop TIC for projects varying in size, scope, duration and complexity
- Provide cost reporting and forecasting against provided estimates
Project Management
- Fast Track Project Execution
- Formal Project Communication Methods
- Strategy Development
- Financial Management
- Critical Path Schedules
- Project Risk Assessment & Risk Mitigation
- Cost Tracking & Reporting
- Cost Estimating
- Feasibility Analyses to Guide Strategic Business Decisions
- Commissioning/Start-Up Planning