Protecting Critical Production Lines from Voltage Transient Damage

Automotive battery manufacturing facility, Pune — persistent PLC and VFD failures traced to severe transient disturbances generated by continuous switching of industrial loads across the distribution system.

Industry

Battery Manufacturing

Location

Pune, India

Service

PQ Audit + TVSS

Year

2024

1 The Challenge

Repeated equipment failures with no clear cause

Persistent PLC and VFD malfunctions, frequent electronic card failures, and nuisance tripping across production lines — with no apparent cause from standard maintenance checks.

•275 transient events in 30 minutes at main production panel — up to 457V magnitude

•158 events in 60 min on production line — neutral-to-ground voltage reaching 11–12V

•56 events in 40 min on another line — high oscillatory and impulse transients

•101 events in 53 min — automation systems under continuous stress

•Root cause: continuous switching of industrial loads generating repetitive transients across the distribution system

2 The Action

Measure first — then solve

Pre-installation Power Quality Audit using a Class A analyser — capturing transient events, magnitudes, and neutral-to-ground voltage across all critical panels before recommending any solution.

→Site measurement at all critical production panels — transient capture at 200kS/sec

→Root cause analysis — identified transient sources and propagation paths

→TVSS installed at main incomer (L-L-L-G) and sensitive load incomers (L-N-G)

→Dedicated surge protection at each VFD, PLC, and SMPS section

→Post-installation audit conducted 3 months later to verify performance through data

3 The Results

Verified by post-installation measurement

93%

Reduction in transient events

0.72V

Neutral-to-ground voltage achieved

Transient events (30 min) 275 → 20

Transient magnitude Up to 457V → Very small

Voltage profile Unstable → Stable

N-G voltage Elevated → 0.72V

4 The Benefits

Impact across three dimensions

✓Technical — Drastic reduction in transient magnitude and frequency, improved voltage stability, safe neutral-to-ground voltage levels

✓Operational — Reduced PLC and VFD malfunction incidents, reduced unplanned production downtime, improved process continuity

✓Maintenance — Fewer electronic card failures, lower frequency of maintenance interventions, reduced risk of unexpected shutdowns

✓Long-term — Extended service life of sensitive automation equipment and reduced total cost of ownership