Pakistani Factory Power Quality Audit Checklist 2026 — Voltage, Harmonic, Earthing, MD Assessment

The 8 audit dimensions — what gets measured, with what instrument

1. Voltage stability (IEC 61000-4-30 Class A)

• Logger: 3-phase voltage recorder for 7 days minimum
• Metrics: V_nominal ±10% deviation; sag/swell count and depth; flicker P_st/P_lt
• Pakistani-specific findings: 5-15 voltage sags/day common; 380-400V LL deliveries vary by 8-12% during peak hours
• Remediation: voltage protector at main + AVR/stabilizer on sensitive loads

2. Harmonic distortion (IEEE 519 + IEC 61000-4-7)

• Logger: power quality analyzer with THD measurement on all 3 phases
• Metrics: V-THD <8% per IEEE 519; I-THD <5% at PCC; individual harmonic distortion limits
• Pakistani-specific findings: VFDs without harmonic filters cause 12-25% I-THD; LED lighting clusters cause 30%+ THD on lighting circuits
• Remediation: 5% line reactors on VFDs; passive harmonic filters; 12-pulse VFD topology for large drives

3. Earthing resistance + bonding integrity

• Tester: 3-pole earth resistance tester (e.g., Megger DET3TC) or clamp-on earth tester
• Metrics: Earth electrode resistance <5Ω; all metallic enclosures bonded; equipotential bonding to water/gas/structural metalwork
• Pakistani-specific findings: rusted earth rods at 25-60Ω common; missing cross-bonding to factory metal sheds
• Remediation: drive additional 1.5m copper rods in parallel; pack pit with bentonite + charcoal; bond all metalwork to MET

4. Power factor at PCC

• Logger: 3-phase PQ analyzer with PF calculation
• Metrics: kW, kVAr, kVA, PF over time; weighted-average monthly PF for billing
• Pakistani-specific findings: motor-heavy factories often at PF 0.65-0.78; commercial sites 0.80-0.88
• Remediation: automatic PFC bank (BSMJ 440V capacitors + JKW5C controller) sized to lift PF to 0.95+

5. MD profile + ToU exposure

• Logger: 15-min interval kW + kVA log for 30 days
• Metrics: highest 15-min average kW (billing MD); concentration in peak ToU hours; load-factor (avg kW / peak kW)
• Pakistani-specific findings: most factories have load-factor <0.45 (highly peaky); MD bills 2-3× steady-state would imply
• Remediation: load-stagger motor starts; shift discretionary load to off-peak; install WiFi smart breaker + automation

6. Neutral conductor + N-E voltage

• Tester: multimeter measuring N to E voltage at sub-DBs (should be <2V); thermal imaging of N busbar
• Metrics: N-E voltage stability; N conductor temperature rise; unbalance between L1-N, L2-N, L3-N
• Pakistani-specific findings: broken-neutral hazards common after lightning; phase unbalance 5-15% on 3-phase services
• Remediation: separate N from PE downstream of MET; install voltage protector to disconnect on N-E rise; balance loads across phases

7. Insulation Resistance (IR) — Megger tests

• Tester: 500V or 1000V insulation tester
• Metrics: motor winding IR >1MΩ per kV rated + 1MΩ; cable IR >0.5MΩ; transformer IR >100MΩ
• Pakistani-specific findings: motors in dusty/humid environments drop to 0.2-0.5MΩ within 12-18 months; cable IR drops on UV-exposed PVC
• Remediation: annual IR test schedule; varnish-dip + dry-out for low-IR motors; replace UV-degraded cable

8. Earth-leakage continuous monitoring

• Logger: clamp-on residual current meter; alternatively 30 mA RCD trip-history log
• Metrics: standing leakage <10 mA per circuit; sudden leakage spikes indicating fault propagation
• Pakistani-specific findings: industrial heating elements leak 5-15 mA standing (high but acceptable); VFD motor frames leak 20-40 mA due to PWM common-mode
• Remediation: Type B RCBO on VFD circuits; 300 mA Type B RCD upstream; isolate leaky circuits

Audit deliverables (what you should expect)

1. Executive summary — 1 page with traffic-light scorecard (red/amber/green) on each of the 8 dimensions
2. Detailed measurements + time-series charts — voltage events, THD trends, MD profile, PF over week
3. Photographic survey — earth pits, DB box thermal images, panel layout with annotations
4. Prioritised remediation list — ranked by ROI months + safety impact
5. Cost-benefit table — each remediation with installed cost + annual saving + payback months
6. Compliance gap analysis — IEC / NEPRA / DISCO Distribution Code violations
7. Re-audit schedule — recommended frequency (annual / 18-month / 24-month)

Typical findings from Pakistani factory PQ audits

When to audit (frequency)

• Annual: industrial sites >500 kW, hospitals, data centres, food/pharma processing
• Bi-annual (18 months): light industrial 100-500 kW, commercial buildings >10 floors
• Tri-annual (36 months): small commercial <100 kW, retail
• Trigger-event audits: post lightning strike, post-fire, post major equipment damage, post DISCO meter swap

Common Pakistani PQ-audit mistakes

1. Single-point measurement — takes 1-minute snapshot vs 7-day continuous log. Misses transients, sag/swell events.
2. Skipping the harmonics analysis — "we don't have VFDs" — but every LED light + computer power supply contributes; modern offices easily hit 8% I-THD without any motor drive.
3. Not measuring during peak ToU — PQ during 11 PM is best-case; the real test is 6-9 PM when grid is most stressed.
4. Earthing checked only at main MET — sub-DB earth bonds often missing or corroded. Test every sub-DB independently.
5. No before/after measurement of remediation — install PFC bank but never measure post-install PF. Half of Pakistani PFC banks are mis-sized.
6. Auditor without IEC 61000-4-30 Class A instrument — cheap meters don't capture sub-cycle events. Insist on Class A logger.

Related

MD Penalty Calculation · PFC Capacitor Buyer Guide · Pakistani Earthing Systems Guide · SPD Installation Guide