Ensure Reliability of Your Critical Underground Distribution
High voltage cables represent 60% of unplanned substation outages, yet they're the least visible component. Cable failures occur without warning, causing catastrophic equipment damage and extended downtime averaging 48-96 hours.
Proactive cable testing and diagnostics detect developing insulation problems years before failure, enabling planned replacement and preventing emergency outages that cost facilities $50K-$500K+ per event.
High voltage cable services encompass testing, diagnostics, maintenance, and repair of medium voltage (5-35kV) and high voltage cable systems. These services include:
Diagnostic Testing
VLF hipot, tan delta, partial discharge testing
Fault Location
TDR, impulse, and bridge methods for pinpointing faults
Preventive Maintenance
Scheduled testing and condition assessments
Emergency Repairs
24/7 fault location and cable replacement
Services cover all cable types: XLPE, EPR, PILC (paper-insulated lead covered), shielded, non-shielded, and applications including substation feeders, underground distribution, and industrial plant systems.
Cable failures are explosive events. Insulation breakdown creates arcs that vaporize conductor material, generating pressures exceeding 10,000 psi. The resulting explosion destroys adjacent cables, damages terminations, and can rupture concrete vaults. Repair requires excavation, emergency cable procurement, and multi-day outages.
Real Example:
Hospital's 30-year-old 15kV feeder cable failed during peak load on a summer afternoon. The explosion destroyed three adjacent cables in the vault and damaged the switchgear termination compartment. Emergency generators sustained critical loads, but entire facility operated at reduced capacity for 11 days during repair. Total cost: $780K including cable ($45K), emergency labor ($120K), switchgear repairs ($85K), and generator fuel/rentals ($530K). Annual cable testing: $8K.
Modern diagnostic testing identifies degrading insulation before failure. Tan delta and partial discharge measurements detect water treeing, insulation aging, and defective terminations. Trending test results over years provides clear warning when replacement is needed, enabling planned outages during favorable conditions versus emergency response.
Cable systems properly maintained and monitored operate reliably for 40-50 years. Cables without condition monitoring often fail at 20-30 years. With replacement costs of $100-$500 per foot installed, life extension through testing and maintenance generates enormous ROI.
When cables fail, every hour matters. Professional fault location services pinpoint failures within feet using TDR and impulse methods, minimizing excavation and repair time. Without these services, facilities resort to trial-and-error excavation that extends outages days longer and costs 5-10x more.
Water penetrates cable insulation through damaged jackets, defective splices, or terminations. Once inside, moisture creates conductive "trees" that grow through insulation over years. Tan delta testing detects elevated moisture before catastrophic breakdown. Early detection enables termination replacement or cable section replacement before complete failure.
Insulation degrades from electrical stress, thermal cycling, and chemical reactions. XLPE cables experience oxidation; PILC cables suffer dielectric breakdown. VLF hipot and partial discharge testing reveal degradation severity. Condition-based replacement prevents sudden failures and enables budgeting for planned upgrades.
Poor installation, moisture ingress, or material degradation cause terminations and splices to fail. These failures often occur at stress cones where electric fields concentrate. Partial discharge testing identifies defective terminations before failure. Preventive replacement of failing terminations costs $5K-$15K; emergency cable replacement costs $100K-$500K.
Improper shield grounding causes circulating currents that overheat cables, or floating shields that lead to dangerous voltage rise. Shield continuity testing and induced voltage measurements identify grounding defects. Correcting grounding issues prevents thermal damage and personnel safety hazards.
When cables fail without proper fault location, repair becomes guesswork involving extensive excavation. Professional TDR and impulse testing pinpoints faults within 3-10 feet accuracy, even in complex routes with multiple bends and splices. This eliminates exploratory digging that damages infrastructure and extends outages.
Best Practice: Implement condition-based monitoring for critical feeders. Annual testing establishes trends that predict failures 2-5 years in advance.
Typical Duration: Complete diagnostic testing of a 3-phase cable circuit requires 6-12 hours depending on cable length and accessibility. Fault location services typically complete within 4-8 hours.
$100K-$500K+
Emergency cable failure and repair costs
$5K-$15K
Comprehensive diagnostic testing per circuit
10-50x
ROI from preventing ONE emergency failure
Defines test procedures, voltage levels, and acceptance criteria for cable systems including VLF hipot, tan delta, and partial discharge testing.
IEEE 400.2 (field testing), 400.3 (partial discharge), and 400.4 (VLF testing) provide comprehensive guidance on cable diagnostic methods and interpretation.
Covers cable design, installation, and testing requirements for various cable types and voltage classes.
Recommends cable testing intervals based on voltage class, insulation type, and operating environment.
Proactive cable testing provides years of advance warning before failures occur.
📧 support@clarkte.com | ☎️ +1 (617) 396-4632 | 📍 Boston, MA