MTA-MA-022

Administrative Items
Date	12/15/20
Functional Area Where Benefits Will Be Realized	Maintenance Engineering
Reference Implementation Guidance	Electrical Signature Analysis (ESA) for On-Line Equipment Condition Monitoring (EPRI 3002017660) Predictive Maintenance Technologies: An Overview of Motor Current Signature Analysis and Electromagnetic Signature Analysis (EPRI 3002003913)
Industry SME	EPRI – Michael Taylor EPRI – Steve Lopez Contact: NuclearPlantMod@epri.com
Previous Implementation	Please contact EPRI for implementation examples and contacts.
Implementation Enablers	MTA-MA-003 – Implement a Wireless Network Infrastructure Using a Distributed Antenna System (DAS) MTA-MA-004 – Implement a Wireless Network Infrastructure Using WiFi
SWEEP Score	Cost – Level 2 – The cost for design, installation, and material of the necessary equipment for ESA is approximately $5 million. Savings – Level 0 – Savings are not evaluated because ESA is an enabler. Payback – Level 0 – Payback is not evaluated because ESA is an enabler. Licensing Readiness – Level 3 – No licensing changes are required for ESA. Technology Readiness – Level 2 – The technology is ready for pilot implementation at nuclear plants. Implementation Proficiency – Level 3 – ESA can be implemented by all sites regardless of digital experience.
Applicability	All reactor types All geographic regions
Keywords	Electric signature analysis; ESA; motor current signature analysis; MCSA; continuous online monitoring; COLM
Business Case Analysis Cross-Reference	N/A

Description

Downtime of critical motors is a significant contributor to decreased nuclear plant reliability. Providing regular or continuous monitoring of these systems using Electrical Signature Analysis (ESA) can assist in eliminating unnecessary shutdowns through early detection of equipment degradation, avoid unplanned equipment downtime and facilitate planning proper maintenance activities, improving equipment and plant reliability.

ESA uses both the voltage and current measurements, typically acquired from a motor control center (MCC) or switchgear, to identify motor faults such as phase imbalance, power factor, power harmonics, and rotor bar issues.

Techniques employed in an ESA include:

• Motor current signature analysis (MCSA)
• Voltage signature analysis (VSA)
• Instantaneous power signature analysis (IPSA)
• Motor torque analysis (MTA)
• Electromagnetic signature analysis (EMSA)

ESA is considered an enabling technology for Continuous Online Monitoring (COLM) of motors and motor‑driven equipment (e.g., MTA-MA-002 – Reduce Motor Maintenance Costs Through Online Monitoring, MTA-MA-009 – Reduce Pump Maintenance Costs Through Online Monitoring).

Benefits

Benefits Estimate

Level 0 – Savings are not evaluated because the technology or process improvement is an enabler, which does not inherently produce cost savings but permits implementation of other improvements.

Benefits Description

• ESA is better suited to diagnose certain faults (e.g., stator winding faults) than MCSA alone.
• Improved insight into motor health.
• Potential to detect incipient failures before major damage and to avoid forced equipment outages.

Costs and Schedule

Cost

Level 2 – The cost for design, installation, and material of the necessary equipment for ESA is approximately $5 million.

Schedule

One to three years – Installation of measurement equipment on the bus feeding the motor requires de‑energizing the bus. Current experience indicates that instrumentation of one train per refueling outage is realistic.

Scope Context

Per unit

Risks

A library of fault signatures is not currently available but is under development by EPRI. Tests to support development of a fault library are scheduled for late 2020. ESA can be conducted without a fault library but troubleshooting of the motor will require additional effort. Vendor experience may compensate for the lack of a fault library.