Power cables serve as the core medium for power transmission in urban distribution networks, industrial plants and new energy power stations. With large-scale underground grid renovation and booming renewable energy construction, cable usage has grown explosively. During production, laying and long-term operation, cables inevitably suffer insulation damage, moisture ingress and aging, triggering short circuits, earth faults and widespread power outages. The dedicated high‑voltage power supply for cable fault detection and location is critical core equipment. It provides stable DC high voltage and adjustable pulse output for flashover breakdown, pulse reflection testing and high‑voltage bridge measurement, enabling fault point breakdown, test signal excitation and precise distance positioning. Its pulse energy, voltage range, waveform accuracy and field adaptability directly determine positioning precision, detection efficiency, repair speed and power restoration time. Cable fault diagnosis imposes far stricter requirements than conventional high‑voltage power supplies.
Eight extreme technical challenges: 1.Wide high‑voltage output & large pulse energy: Covers 0.4kV low‑voltage to 500kV ultra‑high‑voltage cables, including low-resistance, high-resistance, short-circuit, open-circuit and flashover faults. DC output ranges from 0~60kV, 0~120kV, 0~200kV up to 500kV; single pulse energy ≥1000J. Supports DC, single pulse, repetitive pulse and impulse modes for all fault types. 2.Precise pulse waveform control for high positioning accuracy: Adapts to TDR pulse reflection, pulse current and acoustic‑magnetic synchronous methods. Pulse width adjustable 1μs~1000μs, rise time ≤100ns, amplitude repeatability ≤±1%. Pre-positioning accuracy ≤0.5%, precise positioning ≤0.1m. 3.Strong load compatibility & reliable high-resistance breakdown: Accommodates insulation resistance from several ohms to hundreds of MΩ, and large capacitive cables from tens of nF to several μF. Ensures fast charging, stable flashover and continuous discharge for long‑distance high‑impedance faults. 4.Portability & harsh field environment adaptability: Compact lightweight integrated design for frequent transportation in trenches, tunnels, urban roads and mountain areas. Stable operation at −20℃~+50℃, 90% RH high humidity, heavy dust and vibration; IP54 protection grade. 5.High safety & comprehensive non-bypass protection: Full multi-level protection including overvoltage, overcurrent, short circuit, overtemperature, zero-voltage interlock, automatic residual charge release, door interlock and emergency stop. Zero-voltage soft start and controlled shutdown prevent electric shock and insulation damage. 6.Low noise & strong EMC immunity: Restrains ripple ≤0.1% peak-to-peak; eliminates narrowband spurs in detection frequency bands. Maintains signal integrity for millivolt-level weak reflected pulses under strong substation and industrial electromagnetic interference. 7.Intelligent automatic detection & programmable control: Seamless connection with fault analyzers and upper computers; automatic voltage adjustment, flashover recognition, pulse triggering and fault distance calculation. Preset test modes reduce reliance on operator experience and improve efficiency. 8.Metrological traceability & standard compliance: Fully traceable to national standards per JJG 313, JJG 755, GB/T 16927.1 and IEC 60270, ensuring legal validity and accuracy of official fault diagnosis reports.
This methodology establishes a full-process technical framework covering wide-range HV topology, precise pulse shaping, high-energy breakdown optimization, lightweight design and field environmental protection. It supports fault detection, location and withstand voltage tests for 0.4kV~500kV power cables, delivering standardized design principles for core component localization and performance upgrading. The universal core architecture adopted is:Series resonant charging + Marx pulse discharge topology + fully digital FPGA pulse control. It overcomes traditional limitations such as narrow voltage range, poor pulse accuracy, heavy weight and weak field adaptability. Series resonant charging realizes high-efficiency constant-current fast charging for large capacitive cable loads with high power factor and inherent short-circuit current limiting. The Marx multi-stage capacitor charge-discharge structure generates flexible high-energy pulses with precise amplitude, width and repetition frequency, fully matching DC withstand, flashover impulse and pulse reflection testing. FPGA-based digital control achieves nanosecond-level waveform precision for superior positioning performance, while integrated lightweight construction ensures mobile field deployment.
1.Wide-range high-voltage & high-energy topology design: •Optimized series resonant constant-current charging achieves charging efficiency ≥95% and power factor ≥0.95, enabling rapid charging for long capacitive cables. Natural short-circuit protection ensures device safety. Supports 0~60kV / 0~120kV / 0~200kV DC output (expandable to 500kV), with constant-current fast charge and constant-voltage withstand modes. •Marx multi-stage pulse discharge delivers adjustable high-voltage pulses; single pulse energy ≥1000J. Precise control of pulse width (1μs~1000μs), rise time ≤100ns and amplitude repeatability ≤±1%. Low-inductance layout ensures smooth stable pulse waveforms for pulse current and acoustic‑magnetic synchronous positioning. •Integrated multi-mode output integrates DC HV, single pulse, repetitive pulse, impulse and burn-through modes for one-click switching. Completes burn-through, pre-location, precise location and withstand testing with a single device, greatly improving on-site efficiency.
2.Precise pulse shaping & positioning adaptation: •FPGA core with high-stability OCXO achieves clock jitter ≤10ns and independent programmable multi-channel triggering with ≤10ns step adjustment. Synchronous control of Marx switches guarantees fast clean pulse rising edges for high-resolution fault reflection analysis. •Optimized waveforms for mainstream methods: sharp stable pulses for pulse current pre-location (≤0.5% accuracy); adjustable repetitive energy pulses for acoustic‑magnetic synchronous pinpointing (≤0.1m); ultra-stable DC output for bridge-based low-resistance fault measurement. •Adaptive charging for large capacitive cables supports long-distance high-capacity loads with adjustable charging current up to 100mA; impedance matching eliminates pulse distortion and ensures complete identifiable reflected signals. •Intelligent flashover recognition captures real-time voltage/current waveforms, automatically raising voltage for unbroken faults and maintaining stable excitation after successful breakdown, realizing adaptive automatic testing without manual intervention.
3.Full load compatibility & high-resistance breakdown enhancement: •Stable operation from no-load to full short-circuit, covering 0Ω~1000MΩ insulation resistance. Delivers up to 200kV HV for reliable breakdown of severe high-resistance flashover faults; inherent current limiting protects equipment even under direct short-circuit conditions. •Dedicated burn-through mode outputs 0~30kV / up to 500mA DC to rapidly reduce high-resistance impedance into detectable low-resistance faults; intermittent burn-through prevents unnecessary expansion of cable insulation damage. •Adjustable pulse repetition frequency (0.1Hz~10Hz) ensures stable continuous excitation for intermittent flashover faults. •Multi-range segmented output covers low (0~10kV), medium (0~30kV), high (0~60kV) and ultra-high (0~120kV) ranges, fully covering 0.4kV~500kV cable categories with factory-calibrated full-scale accuracy.
4.Portable lightweight & high power density engineering: •High-frequency design (50kHz~200kHz) miniaturizes transformers, inductors and capacitors; planar integrated magnetics reduce overall size. Multi-layer PCB and 3D compact layout achieve power density ≥200W/in³. Lightweight models: ≤15kg (60kV/2kW), ≤25kg (120kV/2kW), enabling single-person handling. •All-in-one integrated host integrates HV generation, control, sampling and HMI; modular architecture supports flexible voltage/energy configuration and easy maintenance; ultra-high-voltage versions adopt split control/main HV cylinder design for convenient on-site deployment. •High-strength lightweight aluminum alloy chassis, low-loss nanocrystalline magnetic cores and high-energy-density film capacitors reduce weight; combined natural cooling + intelligent air cooling optimizes thermal layout without bulky heat sinks.
5.Harsh outdoor environmental ruggedization: •Industrial wide-temperature components (−40℃~+85℃) ensure full-power operation from −20℃ to +50℃; adaptive temperature compensation maintains stable output accuracy under extreme cold and hot field conditions. •Fully sealed IP54 enclosure with conformal PCB coating, anti-corrosion surface treatment and waterproof aviation connectors resists rain, dust, moisture up to 90% RH. •Reinforced mechanical structure with finite element vibration optimization withstands 30g impact and 10g random vibration for reliable performance during transportation and rough on-site handling. •Wide AC input (85VAC~265VAC) adapts to unstable grid power and generator supply; reserved external battery interface supports emergency testing in non-mains areas.
6.Full-dimensional non-bypass safety protection: •Independent hardware emergency stop + door interlock + HV output interlock + earthing interlock cut off high voltage instantly under unsafe conditions; strict interlock logic prevents accidental energization. •Zero-voltage startup lock ensures voltage rises gradually from zero; automatic controlled shutdown; dual redundant residual charge release reduces stored energy to safe levels within 500ms; high-voltage indicator lights and audible alarms warn operators of live circuits. •Dual hardware-software protection: ultra-fast hardware comparators (<1μs response) handle overvoltage, overcurrent, short circuit and overtemperature with non-bypass highest priority; software complements undervoltage lock, cabinet door protection and user-defined upper voltage limits to avoid cable overstress. •Three-level user permission management and mandatory confirmation for critical operations prevent misoperation by untrained personnel.
7.Low noise EMC & anti-interference design: •Multi-stage π-filtering on charging circuits and RC suppression on pulse outputs control DC ripple ≤0.1%; soft-switch technology eliminates switching spikes and narrowband interference, protecting weak millivolt-level reflected fault signals. •Fully shielded steel enclosure (shielding efficiency ≥60dB); independent shielded cavities for power, control and sampling units; HV coaxial output cables and double-shield signal cables suppress radiation and crosstalk. •Three-level port surge protection withstands ±4kV ESD, ±4kV EFT and ±6kV lightning surges; differential sampling + fiber isolation achieve common-mode rejection ≥120dB for stable detection in strong electromagnetic field environments. •Independent star-point earthing strictly separates power, analog, digital and shielding grounds to eliminate ground-loop interference and improve signal SNR.
8.Intelligent control & industry standard compliance: •Industrial touchscreen and upper-computer software support visualized parameter setting, one-click mode switching, real-time waveform monitoring and automatic full-process testing including burn-through, pre-location, precise calculation and report generation. Rich communication interfaces (RS485, Ethernet, USB) enable seamless linkage with mainstream third-party fault analyzers. •Fully compliant with GB/T 16927.1, IEC 60270, JJG 755 and DL/T 303; complete metrological traceability ensures authoritative test results. Applicable to power cables, control cables, mining and marine cables in municipal, new energy, industrial, subway and petrochemical industries; available in portable, vehicle-mounted and fixed cabinet configurations.
Summary: This integrated technical framework solves core bottlenecks of traditional cable fault detection power supplies, achieving ultra-wide 0.4kV~500kV coverage, high-energy Marx pulse output, nanosecond-level precise waveform control, excellent high-resistance flashover capability and lightweight portable field design. It provides core independent technology for domestic cable fault diagnosis equipment, supporting efficient intelligent operation and rapid power restoration for the entire power grid.