Intelligent Upgrade Solution for Outdoor VT/PT: Smart Sensing Hub in New Power Systems

I. Solution Positioning & Technical Vision
At the critical stage of the evolution from smart grid construction to the digital power grid, this solution transforms outdoor Voltage Transformers (VT/PT) into core nodes within the holographic sensing network of smart substations. By integrating embedded sensing, IoT communication, and artificial intelligence technologies, it achieves dual breakthroughs in device state observability and operational controllability, supporting the transformation of grid dispatch and protection systems towards data-driven operation.

II. Core Technical Architecture

End-to-End Digital Access

Technical Module	Functional Implementation
Native Digital Interface	Standard IEC 61850-9-2LE protocol digital output interface, supports direct connection to Merging Units (MU)
Electrification Sensing Revolution	Utilizes capacitive voltage divider sensing units, outputs fully digital signals (Accuracy: Class 0.2)
Open Protocol Stack	Compatible with IEEE C37.118.2 / GB/T 32890 and other standards, eliminating protocol silos

Edge Intelligence Diagnostic Engine

Three-Tier Analytics Architecture: Device-layer raw data → Edge computing node feature extraction → Cloud platform deep decision-making
Predictive Maintenance Models: Health assessment system based on LSTM-RNN algorithms, enabling:
▶ Insulation degradation trend prediction (>92% warning accuracy 7 days in advance)
▶ Mechanical fault root cause analysis (Supports SF6 leakage location accuracy ±0.5kPa)
▶ Partial discharge pattern recognition (Classification accuracy meets IEC 60270 Standard Class III)

III. System-Level Value Creation

Grid Control Enhancement

Protection action latency compressed to ~15ms level (40% improvement vs. traditional solutions)
Phasor Measurement Unit (PMU) synchronization accuracy ≤ ±0.01°
Supports millisecond-level reactive power compensation decisions

Asset Lean Management

Monitoring Dimension	Core Diagnostic Indicators	Technical Implementation	Maintenance Benefits
Insulation Life Assessment	▪ Degree of Polymerization (DP) curve ▪ Furfural content (Warning ≥0.1mg/L) ▪ Dissipation Factor (tanδ growth rate)	Embedded oil chromatography sensor + On-line pyrolysis monitoring unit	▶ Maintenance cost reduction ≥35% ▶ Insulation failure warning 6-8 months in advance ▶ Life prediction error <3 years
Mechanical Condition Monitoring	▪ Vibration spectrum eigenvalues (Energy spectrum in 0.5-2.5kHz band) ▪ SF6 density gradient (≤ ±5% nominal value)	Micro MEMS accelerometer + Laser density sensor array	▶ Unplanned outages reduced ≥60% ▶ Mechanical fault location accuracy ±0.3kPa ▶ Seal failure detection rate ≥98%
Environmental Coupling Adaptation	▪ Temperature-Humidity coupling coefficient (Temp. compensation accuracy 0.05℃/%RH) ▪ Equivalent Salt Deposit Density (ESDD)	Nano-coated temperature/humidity sensor + On-line leakage current analysis module	▶ False alarm rate in extreme conditions down ≥75% ▶ External insulation assessment efficiency improved ≥4x ▶ Cleaning cycle optimized ≥35%
Partial Discharge (PD) Monitoring	▪ UHF/TEV combined discharge pattern (PRPD phase-resolved pattern) ▪ Discharge magnitude (pC) / Repetition rate (n/s)	UHF antenna array + Transient Earth Voltage (TEV) sensors	▶ Early detection rate for insulation defects >97% ▶ PD type recognition accuracy Class II ▶ Testing cost savings ≥50%

New Power System Support
Builds a collaborative "Device-Edge-Cloud" system:

Device Side: Each VT/PT forms an independent sensing cell.
Edge Side: Substation-level smart analysis host enables regional collaboration.
Cloud Platform: Supports 3D digital twin for the health status of grid-wide devices.

IV. Engineering Implementation Path

Hardware Deployment
o Plug-and-Play intelligent component enclosure (Protection class IP68)
o Modular monitoring units support hot-swap replacement
o Passive wireless sensor clusters (reducing wiring complexity by 60%)
Data Integration
Transition Strategy
Provides retrofit kits for traditional electromagnetic PTs:
o External Smart Adapter (supports analog-to-digital conversion)
o Non-intrusive DGA (Dissolved Gas Analysis) breathing membrane gas extraction device
o Scalable TEV sensor arrays

V. Application Results
Practice at a 500kV smart substation demonstrates:

Device condition assessment efficiency improved ≥8x
Early detection rate for insulation defects increased to 97.3%
Maintenance manpower requirement decreased ≥70%
Asset service life extended by 15-20%

VI. Solution Value Summary
This solution evolves outdoor VTs/PTs into integrated smart terminals embodying "Sensing-Analysis-Decision-making," resolving three key contradictions of traditional equipment: analog transmission accuracy loss, offline detection timeliness lag, and isolated device data silos. It provides the foundational sensing cornerstone for building a new digital power grid characterized by "Observability, Measurability, and Controllability", significantly enhancing grid resilience and energy utilization efficiency. This solution stands as a core technological pathway supporting the transformation and upgrade of power systems under the "Dual Carbon" goals.

Note: This solution complies with IEEE P2815, DL/T 860 and other standard frameworks, applicable to scenarios ranging from 110kV to 1000kV.

07/19/2025