Wuhan GDZX Power Equipment Co., Ltd

How to Select the Best Configuration for Power Cable Main Insulation Fault Testing？

To ensure the safe and reliable operation of power systems, it is crucial to locate power cable main insulation faults quickly and accurately. For 35kV, 10kV, and 380V power cable systems with main insulation faults, short circuits, open circuits, grounding, or high-resistance faults, the following testing configurations and methods are recommended. I. Application Scope Applicable to main insulation faults, short circuits, open circuits, grounding, and high-resistance faults in 35kV, 10kV, and 380V power cable systems. II. Testing Objective To rapidly and precisely locate the exact position of the fault point for excavation, repair, and power restoration. For more complex cable faults, the following testing methods are recommended: High-Resistance Fault Elimination Method:Use a high-voltage breakdown source to fully puncture the fault point, then use a fault locator to measure the distance to the fault. Finally, use a pinpoint locator for precise fault location. Conduit Fault Elimination Method:When the cable runs through PE or PVC conduits, sound synchronization and echo within the conduit make it difficult to locate the fault by listening to discharge sounds. The synchronized acoustic–magnetic method combined with noise reduction effectively eliminates this issue. Since magnetic signals are interference-free, they allow for precise pinpointing. Water-Ingress Fault Elimination Method:When a cable fault occurs underwater, the discharge sound becomes muffled, and direct contact with the water surface is restricted, making pinpointing difficult. The synchronized acoustic–magnetic method combined with the step voltage method can effectively resolve this. Magnetic signals remain unaffected, and the step voltage method enables water surface contact for accurate location. III. Testing Solutions Step Test Step  General Solution Function Completion Step 1 Fault Type Identification    Megohmmeter/Multimeter Measurement  Determine the faulty phase and fault type of the cable, prepare for testing Step 2 Fault Distance Measurement Traveling Wave Range Finder (currently in general use), High-Voltage Bridge Measure the distance to the fault point to provide a general range for precise location Step 3 Cable Path Detection Smart Underground Utility Locator Detect the precise path of cables Step 4 Precise Fault Location Acoustic Testing Method, Acoustic-Magnetic Synchronization Method, Step Voltage Method Ultimately pinpointing the exact location of the fault point IV. Recommended Product Configuration for GDZX ZX-A Series Power Cable Fault Testing No. Product Name   Instrument Function 1 ZX-32B Series High-Voltage Signal Generator (Required) Generates high-voltage breakdown fault points (true integration: capacitor and discharge ball gap built-in)(Provides high-voltage signal source for pulse current distance measurement, pulse distance measurement, and precise fault location) 2 ZX-Z10 Cable Fault Locator (Required) Fault Distance Measurement (Automatic distance measurement without manual waveform analysis, foolproof)Automatic Fault Distance Analysis System V3.01, Low-voltage pulse, Pulse current, Remote service (optional features) 3 ZX-A301 Cable Fault Locator (Required) Pinpoint the exact location of the fault point(Waveform display method, intelligent method directly provides acoustic-magnetic delay values, strong noise reduction, adaptive noise reduction, no noise reduction, path compass display, automatic mute) Industry first 4 ZXPD-3000 Cable Path and Identification Instrument (Required) Path detection, screen display of cable location and depth, cable identification, real-time depth measurement, intelligent obstacle avoidance, pipeline survey Scope of Application  Detects various faults in the main insulation of sheathed cables rated at 35kV, 10kV, 380V, etc., including low resistance, high resistance, flashover, open circuits, and ground faults. All the above testing instruments are available with corresponding models on our official website.Contact us today for personalized recommendations and the optimal configuration to meet your testing needs.

Chilean Client Visits GDZX to Deepen High-Voltage Testing Technology Collaboration

On October 9, GDZX welcomed a visiting delegation from Chile. The clients made a special trip to conduct an on-site inspection, focusing on in-depth discussions around high-voltage cable testing equipment and technological collaboration, and have tentatively reached a preliminary cooperation agreement. 01 Conference Exchange Upon the clients’ arrival, GDZX held a brief welcoming meeting. Our representatives extended a warm welcome and introduced GDZX’s development journey and core products through a company video. The clients also shared an overview of their business, highlighting project requirements and technical challenges in 35kV and future 220kV cable testing.     02 Laboratory and production workshop tour Accompanied by our technical team, the clients toured GDZX’s core laboratories and production workshops, gaining a firsthand understanding of the key stages from R&D validation to mass production and delivery. While observing equipment parameter fluctuations on real-time data screens, the clients showed strong interest in the long-term operational stability and data acquisition accuracy of the equipment. During the production workshop visit, the clients focused on the precision machining of core components, the multi-dimensional quality control processes during assembly, and the comprehensive pre-delivery testing standards. They praised the automated inspection equipment and full-process traceability management system, noting that a standardized production system is key to ensuring equipment performance.     03  Showroom Experience Next, the clients moved to the product exhibition hall to gain a comprehensive understanding of GDZX’s offerings: the ZXVLF-80kVB ultra-low frequency high-voltage generator for 35kV cable withstand testing, the ZXJF-2011 digital partial discharge testing system with high-sensitivity detection, the ZXVLF-YJS3 ultra-low frequency dielectric loss high-voltage generator for insulation diagnostics, and the ZXBXZ series series-resonant devices providing solutions for 220kV cable testing. Our specialists provided detailed explanations through physical displays and demonstrations of the operation interfaces, highlighting each device’s innovative design, functional features, and on-site application cases. The clients showed keen interest, frequently stopping to inquire in depth about equipment compatibility and upgrade potential.     04  Workshop Tour Finally, the clients visited the workshop to observe the full production process, from component inspection and module assembly to complete system commissioning. Witnessing that each device undergoes rigorous aging tests and performance calibration before leaving the factory, they expressed appreciation for GDZX’s quality control system, particularly praising the modular design of the series-resonant devices and the craftsmanship of the ultra-low frequency series.            05  Strategic Win-Win Through the on-site visits and technical exchanges, the clients highly praised GDZX’s equipment for its operational stability, advanced technology, and ease of use. They engaged in productive discussions on future collaboration regarding equipment procurement and technical support in the field of high-voltage cable testing. This visit not only deepened the Chilean clients’ recognition of GDZX’s products and technical capabilities but also laid a solid foundation for future cooperation. GDZX will continue to support global power clients in meeting testing challenges with reliable products and professional services, jointly creating a dependable power future.    

How to Choose Insulating Oil Testers? A Complete Guide to Dielectric Strength vs. Dielectric Loss & Resistivity

Both types of equipment are used for testing the electrical properties of insulating oil, but their test parameters and applications differ. Below is a separate explanation: 1.Insulating Oil Dielectric Strength Tester Main Test Items: Breakdown voltage of insulating oil (dielectric strength). Measures the voltage at which the oil sample is electrically punctured by gradually increasing the applied voltage. Purpose: Evaluates the oil’s ability to withstand electric fields. Determines whether the oil contains moisture, impurities, bubbles, or other factors affecting insulation performance. This is the most basic and commonly used test for insulating oil in power systems. Applicable Scenarios: Routine maintenance of oil-immersed equipment such as transformers, reactors, and capacitors. Periodic preventive testing. 2.Insulating Oil Dielectric Loss & Volume Resistivity Tester Main Test Items: Dielectric loss factor (tgδ): Indicates the dielectric energy loss in the oil. Volume resistivity: Reflects the oil’s resistance to leakage current. Purpose: Provides a more detailed assessment of oil aging, moisture content, and dissolved impurities. Can detect potential problems that may not be revealed by dielectric strength testing alone. Offers an in-depth evaluation of both oil quality and equipment insulation condition. Applicable Scenarios: Situations with high requirements for equipment safety and reliability. Acceptance testing of new oil or post-maintenance evaluation of critical equipment. Further diagnosis of abnormal oil samples. How to Choose? Basic Monitoring: If only routine, periodic testing is needed → Dielectric Strength Tester is sufficient. In-depth Diagnosis: If a comprehensive assessment of oil condition (aging, moisture, impurities) is required → Dielectric Loss & Volume Resistivity Tester is recommended. Comprehensive Application: Many power companies use both devices together, first screening with the dielectric strength tester, then confirming with the dielectric loss/resistivity tester. Combined use can build a complete insulating oil testing system, from basic to advanced, providing the most reliable protection for the safe operation of power equipment.

How to Distinguish and Select: Ground Resistance, Loop Resistance, and Insulation Resistance Testers?

This is a common question in electrical testing.Although the names of these three instruments sound similar, their purposes, test objects, and methods are completely different: 1.Ground Resistance Tester What it measures: The resistance between a grounding device and the earth. Ensures that lightning current or fault current can be safely discharged into the ground. Applications: Substation grounding grids Power equipment grounding systems Lightning rod grounding Building grounding systems 2.Loop Resistance Tester What it measures: The contact resistance of high-current circuits, such as switchgear, cable joints, and busbar connections (typically in the micro-ohm range). Focuses on whether the contact points may overheat, ensuring reliable current transmission. Applications: Contact resistance of high-voltage circuit breakers Busbar and cable joint testing Electrical performance testing during factory inspection or maintenance of HV switchgear 3.Insulation Resistance Tester (commonly called “Vibrometer”) What it measures: The insulation resistance between electrical equipment and ground or between phases. Evaluates the insulation condition to prevent leakage current or breakdown. Applications: Insulation testing of motors, transformers, and power cables Control panels and wiring inspection Household appliances insulation check Key Differences Tester Test Object Test Purpose Resistance Range Test Voltage/Current Ground Resistance Tester Grounding system – Earth Check grounding reliability Ohms to tens of ohms Low-frequency current, auxiliary electrode method Loop Resistance Tester Contacts, circuit connections Check contact quality Micro-ohm level High current (tens to thousands of amperes) Insulation Resistance Tester Insulating materials Check insulation quality Mega-ohms to giga-ohms High DC voltage (commonly 500V – 5kV) In simple terms: Ground resistance: checks “how well you are connected to earth” Loop resistance: checks “how good the circuit contact is” Insulation resistance: checks “whether the insulation is reliable”

How to Choose an SF6 Density Relay Tester? Six Key Factors Buyers Should Know

【News】How to Choose the Right SF6 Density Relay Tester? In power systems, the SF6 density relay plays a vital role in ensuring the safe operation of SF6 electrical equipment such as GIS switchgear and circuit breakers. Since it operates infrequently during service, it may suffer from issues like sluggish action, poor contact, or degraded temperature compensation over time. Therefore, regular verification with an SF6 Density Relay Tester is essential to ensure reliable performance. For buyers, facing various models and brands on the market often raises the question: How should I choose the right tester? The following points may serve as a practical guide. 1. Accuracy and Compliance with Standards Accuracy is the top priority when selecting a tester. Choose products that comply with IEC and national power industry standards. Higher accuracy ensures more reliable assessment of relay performance. Check if the device is supplied with a calibration certificate from the manufacturer or a third-party authority. 2. Applicability and Compatibility Since SF6 density relays vary across manufacturers: Confirm whether the tester supports pressure-gauge type, contact-type, and other relay models. Ensure it is suitable for both laboratory calibration and on-site testing. Verify that the interfaces and accessories are universal and easy to connect. 3. Ease of Operation For field engineers, user experience directly affects efficiency: Does the tester support automatic testing / one-key start? Is it equipped with a touch screen and bilingual (Chinese/English) menu for easier use? Can it store test data, export via USB, or print directly, making reporting more convenient? 4. Portability and Structural Design Field testing requires instruments to be durable and portable: Choose models that are lightweight yet robust. Ensure the housing has shockproof, moisture-proof, and dust-proof protection. Check if it comes with a built-in air pump or external gas source option, offering more flexibility. 5. Safety and Environmental Protection With stricter safety and environmental standards, these functions are crucial: The tester should provide overpressure and leakage protection to ensure operator safety. It should include SF6 gas recovery capability to prevent emissions and meet environmental regulations. 6. After-Sales Service and Maintenance A reliable tester is backed by dependable service: Does the supplier provide periodic calibration, technical training, and operational guidance? Is there prompt and professional after-sales support? Are spare parts readily available to ensure long-term use? Conclusion For buyers, choosing an SF6 Density Relay Tester is not just about comparing prices. A wise decision should consider accuracy, compatibility, ease of operation, portability, safety, environmental performance, and after-sales service. Only then can the equipment truly safeguard SF6 electrical devices, reduce maintenance risks, and deliver long-term value.

What’s the Difference Between an Arrester Discharge Counter Tester and a Zinc Oxide Arrester Tester? How to Choose？

In power systems, surge arresters protect transformers, switchgear, and other equipment from lightning and switching overvoltages. To ensure their reliable performance, professional testing instruments are often required. Two commonly used devices are the Arrester Discharge Counter Tester and the Zinc Oxide Arrester Tester. Although both are used in arrester inspections, they differ significantly in function and application. 1. Differences in Function and Test Items Instrument Main Test Items Key Features Arrester Discharge Counter Tester Checks the working status and discharge count of an arrester’s online monitoring device (discharge counter); verifies the connection between the counter and the arrester Compact, lightweight, and easy to operate; mainly used to confirm whether the counter is sensitive and records accurately Zinc Oxide Arrester Tester Measures key parameters of a zinc oxide arrester, such as reference voltage, leakage current, and V–I characteristics Provides a comprehensive assessment of the arrester’s insulation and aging status, serving as an important tool for evaluating arrester health 2. Application Scenarios Arrester Discharge Counter TesterSuitable for routine inspections, quick on-site checks, or acceptance testing of new installations, ensuring the counter is correctly installed and functions reliably. Zinc Oxide Arrester TesterPrimarily used for maintenance and troubleshooting. During annual preventive tests or fault diagnosis, it measures leakage current and other indicators to assess whether the arrester has issues such as moisture ingress, aging, or breakdown. 3. How to Choose Need to quickly verify a discharge counter → Choose the Arrester Discharge Counter Tester for its portability and simple operation. Need a full assessment of arrester performance → Choose the Zinc Oxide Arrester Tester, which provides complete electrical characteristic data, ideal for maintenance teams or laboratories. For large substations or professional service units, it’s recommended to use both: start with the counter tester for routine patrols, then use the zinc oxide tester for in-depth evaluation, creating a complete maintenance system. ConclusionThe Arrester Discharge Counter Tester and Zinc Oxide Arrester Tester are not substitutes but complementary tools for different testing objectives. When purchasing, users should consider their actual testing needs, maintenance schedule, and budget to select the right device—or a combination of both—to better ensure the safe and stable operation of power systems.

When Should You Choose a Zinc Oxide Surge Arrester Tester? – Frequently Asked Questions

Zinc oxide surge arresters (MOAs) protect power equipment from lightning and switching overvoltage. Over time, their insulation and leakage current may change, so regular testing is important. Below are answers to common questions from our customers. 1. Do new arresters need testing?  Yes. Test before installation or commissioning to set baseline data. 2. How often should they be tested?  Every 1–2 years, checking leakage current, resistive current, and reference voltage. 3. When should testing be done immediately?  After: Visible damage (cracks, discharge marks) Moisture or dirt on the base or housing Lightning strikes or switching surges Leakage current alarms 4. During overhauls or maintenance?  Yes. Include surge arrester testing in scheduled inspections or repairs. Benefits of a Tester Accurate leakage current measurement (separates resistive and capacitive parts) On-line testing without disassembly Works with various voltage levels for substations and transmission lines Summary Surge arresters are the grid’s first line of defense. Routine testing with a quality instrument prevents failures and outages.Need advice on test intervals? Contact our team — we’ll create a plan based on your equipment and environment. Tip:A clear testing schedule plus reliable instruments = safe and stable power systems.

Why Choose a Portable Transformer Oil Chromatograph?

A portable transformer oil chromatograph is a high-tech instrument specifically designed for on-site gas chromatographic analysis of insulating oil in power transformers and other oil-filled electrical equipment (such as reactors, instrument transformers, and bushings).Its core purpose is to detect fault-characteristic gases dissolved in oil, diagnose potential internal faults, and serve as a key tool for condition-based maintenance (CBM) and preventive testing in the power industry. Key Concerns for Users: 1.Accuracy and Reliability of Analysis Our device adopts the classic “three-detector process,” completing full analysis of seven dissolved gases (H₂, CH₄, C₂H₄, C₂H₆, C₂H₂, CO, CO₂) in a single injection. The results are highly consistent with those from laboratory-grade chromatographs, with qualitative deviation ≤1% and quantitative deviation ≤3%, ensuring precise and trustworthy data. 2.Portability and Rapid DeploymentWith an advanced compact modular design, the instrument weighs less than 15 kg and comes with a trolley case, making it easy to carry to field sites. It provides timely, accurate data for transformer inspections while saving substantial manpower and time. 3.Intelligent and User-Friendly OperationA fully computerized touch-screen interface allows real-time monitoring of temperature and carrier-gas flow across four channels. Parameters are set with one touch, and users only need simple power-on/off operations to perform routine testing, greatly reducing the operating threshold. 4.Stability and Protection FunctionsThe system features multiple safeguards: automatic bridge-current cutoff when pressure or flow exceeds preset limits, protection of the thermal-conductivity detector in case of carrier-gas loss, and automatic shutdown with fault alerts if temperature control fails—ensuring long-term stable operation. 5.Networking and Data ManagementBuilt-in 10/100 M adaptive Ethernet enables fast remote data transmission. The dedicated chromatograph workstation for power systems supports centralized management of multiple devices, providing trend analysis, over-limit alarms, three-ratio diagnostics, and more to help O&M teams make informed decisions. Technical Advantages at a Glance: Minimum detectable concentration: H₂ 2 µL/L, CO 1 µL/L, CH₄ 5 µL/L, C₂H₄/C₂H₆/C₂H₂ 0.1 µL/L Temperature range: ambient + 4 °C to 450 °C, control accuracy ±0.05 °C Six temperature-control zones, ≥20-step programmed heating Dimensions: 450 × 430 × 230 mm; weight < 15 kg Certification and Market Recognition: This portable oil chromatograph has been tested by the Shandong Provincial Institute of Metrology, with all performance indicators reaching international advanced levels. It was awarded the Shandong Provincial Key New Product title in 2020 and received government funding for technology transformation.The instrument complies with international standards IEC 60567:2011 and IEC 60599:2015.