Handheld inspection instrument (TEV/HFCT/Ultrasonic single function): ¥15,000 - ¥40,000. Suitable for daily inspection of switchgear and cable joints in power supply stations. Professional portable comprehensive analyzer (multi-channel, including UHF/pulse): ¥80,000 - ¥200,000. Mainstream in the market, suitable for maintenance companies and municipal companies for in-depth diagnosis and location. Domestic high-end products are highly competitive in this range. Top-level laboratory/arbitration-level systems (imported OMICRON, etc.): ¥300,000 - ¥800,000+. Suitable for provincial electric power research institutes, large equipment manufacturers, and scientific research institutions. Online monitoring system (single bay/single transformer): ¥50,000 - ¥150,000/set. Used for 7x24 real-time monitoring of important hub substations. 5. Usage precautions and technical difficulties Background noise suppression: The biggest challenge on site is electromagnetic interference (mobile phone signals, corona, radio). Must be proficient in using the instrument's frequency domain filtering, time domain windowing, phase synchronization and other functions. If necessary, build a shielding room or use balanced wiring. Sensor coupling: UHF sensor: Must be tightly attached to the basin-type insulator pouring port or dedicated interface, with coupling agent applied evenly. HFCT: The jaws must be closed tightly and the direction correct (pay attention to polarity). Ultrasonic: Apply coupling agent between the probe and the shell, with moderate pressure. Phase synchronization: The accuracy of PRPD pattern (phase-resolved partial discharge pattern) depends on precise power frequency synchronization. If synchronization is wrong, the pattern will be chaotic and cannot be analyzed. Safety first: When testing on live equipment, must strictly abide by the "Safety Regulations" and maintain safe distance. When using insulating rods to extend sensors, pay attention to mechanical strength. Comprehensive diagnosis: Do not draw conclusions based on only one method. The "electrical-acoustic-optical-thermal" multi-parameter fusion is the standard operating procedure in 2026. For example: UHF detects signal -> ultrasonic locates -> infrared temperature measurement assists verification. Standard basis: Test result judgment should refer to GB/T 7354, DL/T 417, Q/GDW 11060 (switchgear), Q/GDW 11059 (GIS) and other enterprise and industry standards. 6. Typical application scenarios GIS/GIL equipment: UHF method is standard, used to detect fatal defects such as free particles, tip discharge, floating potential. Power transformers: Pulse current method (factory/delivery) + UHF/ultrasonic method (on-site/online), to detect winding insulation and oil-paper insulation defects. High-voltage cables and joints: HFCT method and oscillating wave method (OWTS), to detect water trees and air gaps in XLPE cable body and intermediate joints. Switchgear (10kV-35kV): TEV + ultrasonic live detection, can find insulation aging and poor contact without power outage. Rotating machines: Aging assessment of stator winding insulation. Summary suggestions: For daily inspection (switchgear, cable joints): Choose domestic cost-effective handheld TEV/ultrasonic/HFCT composite detectors (such as Wuhan UHV, Huadian Keyi), priced at 20,000-40,000 yuan, lightweight and practical. For in-depth diagnosis and location (GIS, main transformers, difficult faults): Strongly recommend Wuhan UHV Electric's multi-channel UHF+pulse+ultrasonic comprehensive location system. Its performance is close to OMICRON, but the price is only 1/3 of the latter, and it better understands the interference characteristics of domestic power grids. For provincial electric power research institutes, top laboratories, or international arbitration: The first choice is Austria's OMICRON MPD 800. Although expensive, its data authority and powerful analysis software are irreplaceable.
