Wuhan GDZX Power Equipment Co., Ltd Company News

Introduction The lightning impulse test system is an essential tool in electrical engineering, designed to simulate the effects of high-voltage impulse conditions, such as those caused by lightning strikes or transient overvoltages. This system is used to test the durability and performance of electrical equipment under extreme conditions, ensuring safety and operational reliability. Function of the Lightning Impulse Test System Simulation of Lightning Impulse Conditions: The system replicates the high-voltage pulse environment created by lightning strikes, simulating the conditions under which electrical equipment may be subjected to such transient stresses. By generating controlled impulse voltages, the system allows engineers to observe how equipment behaves under high-stress scenarios. Pulse Voltage Simulation: Lightning and switching operations in high-voltage systems create pulse high voltages, which can induce transient overvoltages in surrounding areas. These pulses can range from tens of kilovolts to hundreds of kilovolts, posing risks to both equipment and personnel. The impulse test system generates these voltages artificially to evaluate insulation performance, equipment durability, and potential failure points. Scientific Research Applications: The system plays a critical role in research areas such as: Insulation performance testing: Studying the breakdown strength of insulation under impulse voltages. Electromagnetic compatibility (EMC): Evaluating equipment's resistance to transient electromagnetic interference. Discharge behavior analysis: Understanding the electrical discharge patterns in insulation materials. Applications in the Power Industry Lightning impulse test systems are widely used across the power industry to ensure the reliability of key electrical components. Common applications include: Routine Testing of Power Equipment: Power Transformers: Verifies the transformer’s ability to withstand transient overvoltages during operation. High-Voltage Switches: Ensures reliable performance during switching operations that generate impulse voltages. Power Cables and Accessories: Tests the insulation and joints to prevent failure under high-voltage conditions. Bushings, Insulators, and Lightning Arresters: Ensures these components can handle the stresses of impulse voltages without degradation. Manufacturing and Quality Assurance: Manufacturers use impulse test systems to comply with international (IEC) and national standards, verifying the performance of equipment before shipment. Installation and Maintenance Verification: After installation or repair, impulse voltage testing ensures the equipment remains in compliance with performance standards and is safe for operation. Key Parameters of Lightning Impulse Testing To conduct meaningful impulse voltage tests, the generated waveforms must adhere to standard specifications. The key parameters of impulse waveforms include: Peak Voltage: The maximum voltage reached during the impulse. This is critical for determining the stress level applied to the equipment. Wavefront Time: The duration taken for the impulse to rise from 10% to 90% of its peak value, which reflects how quickly the voltage reaches its maximum. Wave Tail Time: The time taken for the impulse voltage to fall from its peak value to 50% of the peak, representing the decay rate of the pulse. Standard waveforms include lightning impulse waveforms and operating impulse waveforms, tailored to specific equipment and testing scenarios. Significance of Lightning Impulse Testing Safety and Reliability: Impulse testing ensures that equipment can withstand high-voltage transients without failure, preventing catastrophic accidents and ensuring personnel safety. Compliance with Standards: Conformance to IEC, IEEE, and national standards ensures equipment reliability and operational compatibility across different regions and applications. Predictive Maintenance: Identifying weak points in insulation or structural components during impulse testing can prevent unexpected failures during operation, reducing downtime and repair costs. Improved Design: Data gathered from impulse tests help manufacturers refine insulation systems, improve materials, and optimize equipment designs for better performance under high-voltage conditions. Conclusion The lightning impulse test system is a vital tool for evaluating the transient performance of electrical equipment, ensuring its ability to withstand extreme conditions such as lightning strikes or high-voltage surges. For new engineers and procurement professionals, understanding its functions, applications, and parameters is essential for selecting, maintaining, and designing reliable high-voltage systems. By adhering to standardized testing practices, the power industry can ensure equipment safety, reliability, and compliance with global standards.

The on-load tap changer (OLTC) is a critical component in power transformers, designed to adjust voltage levels under load conditions without disrupting the power supply. Proper maintenance of the OLTC ensures reliable operation and extends the life of the transformer. This guide outlines the essential maintenance practices and requirements for OLTCs, aimed at new engineers and procurement professionals. 1. Pre-Operation Maintenance Checklist Before commissioning the OLTC, the following aspects should be thoroughly checked: Oil Conservator: Verify that the oil level in the conservator is within the normal range and that there are no signs of oil leakage. Ensure the control box is adequately sealed and moisture-proof. Manual Operation: Perform one complete manual operating cycle to confirm: The gear indicator counter operates accurately. The locking mechanism for the limit positions is reliable. The interlocking between manual and electrical controls is functioning correctly. 2. Gas Protection System The gas protection system for OLTCs is essential for detecting internal faults. The requirements include: Protection Functions: Heavy Gas: Triggers a trip signal to disconnect the transformer in case of serious faults. Light Gas: Sends an alarm signal for early fault detection. Installation and Maintenance: Gas relays must be installed in safe and accessible locations. After installing or debugging a gas relay, operators should immediately purge any air (deflate) from the gas relay to ensure accuracy and reliability. 3. Electrical Control Inspection To ensure proper electrical operation of the OLTC: Control System: Verify that the electrical control circuit functions correctly and that power supply adjustments can be made seamlessly. Terminals and Connections: Inspect all terminals for good contact to avoid loose connections that may lead to malfunctions. Motor Operation: Confirm that the driving motor rotates smoothly, the steering is correct, and the fuse rating is appropriate (2–2.5 times the motor’s rated current). 4. Voltage Adjustment and Monitoring The on-duty personnel should perform voltage adjustments based on operational requirements: Manual Voltage Adjustments: Adjust the voltage automatically according to dispatcher's instructions, following the voltage curve and signal. Monitoring: Monitor the changes in tap action voltage and current for each operation. Record the operational data once per shift to ensure traceability and identify irregularities. 5. Parallel Operation of Tap Changers Special precautions must be taken when operating two OLTCs in parallel: Load Current Limits: Tap change operations are permitted at 85% of the rated load current, but continuous tap changes on the same transformer are prohibited. Sequential Operation: Complete the tap change operation on one transformer before initiating the tap change operation on the other. No-Load Tap Changer Adjustment: When operating with a no-load tap changer transformer, ensure the OLTC is switched on first. Adjust both transformers to the same or similar tap positions before parallel operation. It is strictly prohibited to adjust tap positions of the no-load tap changer while in parallel operation. 6. Oil Quality Supervision and Inspection The quality of the oil in the OLTC must be monitored regularly to maintain its insulating properties: Inspection Cycle: Conduct an oil pressure test every 6 months. The breakdown voltage of the oil should meet the following criteria: ≥ 30 kV/2.5 mm: Normal operation. 25–30 kV/2.5 mm: Stop the pressure regulation controller and prepare for maintenance. < 25 kV/2.5 mm: Halt all voltage regulation operations and arrange for an oil change. Oil Replacement: Replace the oil every 2–4 years or after 5000 operations. For equipment nearing 10,000–20,000 operations, inspect and replace the oil as part of routine maintenance. 7. Tap Changer Core Inspection Regular inspection of the tap changer core ensures optimal performance: Initial Inspection: Inspect the tap changer body after 1 year of operation or 5000 operations. Subsequent Inspections: Perform inspections every 3–4 years or after cumulative operations of 10,000–20,000 cycles. Imported Equipment: Follow the manufacturer's specific maintenance guidelines for imported OLTCs, typically combining core inspection with transformer overhauls. Conclusion Proper maintenance of on-load tap changers is vital for ensuring transformer reliability and extending the operational life of power systems. By following these guidelines, engineers and procurement professionals can mitigate potential failures, improve operational efficiency, and maintain safety standards. Understanding these requirements will enable informed decision-making in maintenance planning and equipment management.

Causes of Partial Discharge Partial discharge (PD) occurs in insulating materials when localized electrical stress exceeds the dielectric strength of the material in specific areas, typically within air gaps, oil films, or surfaces. Key causes include: Localized Electric Field Concentration: PD is triggered when the local field strength in a gas, liquid, or weak dielectric region exceeds the breakdown field strength. This often occurs in insulation structures with sharp edges or imperfections. Example: The concentrated electric field at the edge of electrodes or slots of high-voltage motor coils. Manufacturing Imperfections: During manufacturing, insulating materials may develop air bubbles, oil films, or voids that lower the breakdown strength compared to solid insulation. Example: In cast transformers, plastic cables, and oil-immersed insulation systems, such defects are common. Electrical Stress: AC Voltage: PD occurs most commonly under sinusoidal AC voltage due to the continuous stress imposed by alternating cycles. DC Voltage: Although less frequent, PD under DC voltage can still occur but at much lower repetition rates than AC. Corona Discharge: At exposed electrode edges, corona discharge in air generates reactive byproducts like ozone, which can chemically degrade surrounding materials. Impacts of Partial Discharge Partial discharge significantly affects the lifespan and reliability of electrical insulation systems. Key impacts include: Insulation Degradation: Physical Effects: Each discharge produces high-energy electrons, causing micro-cracking, weakening the insulation structure. Chemical Reactions: Charged particles and reactive gases generated by PD (e.g., ozone) degrade the molecular structure of insulation. Internal and Surface Discharge: Internal Discharge: Happens within voids, bubbles, or oil films, leading to localized insulation breakdown. Surface Discharge: Occurs along the interface of insulation and air or oil, especially in areas with uneven field distribution. Critical Component Damage: Common in high-voltage equipment such as transformers, cables, capacitors, and motor windings. Over time, repeated PD activity accelerates insulation aging, leading to equipment failure. System Reliability: PD-related insulation failures are a leading cause of faults in high-voltage power systems, especially in ultra-high voltage transformers. Solutions to Partial Discharge Addressing partial discharge requires proactive design, monitoring, and testing strategies. Below are effective approaches: 1. Design Improvements Minimize field concentration by using rounded electrode edges and optimized insulation structures. Eliminate voids and air gaps during manufacturing by applying vacuum impregnation techniques in oil-paper insulation. 2. Testing and Detection Factory Testing: During manufacturing, conduct PD testing on each unit to ensure insulation integrity. Ensure working field strengths are below the initial discharge field strength of the insulation material. On-Site Testing: Perform partial discharge tests during transformer installation and handover to identify latent defects. Monitor gas content in transformer oil; high gas concentrations indicate insulation breakdown. 3. Online Monitoring Real-time monitoring of insulation systems provides early warning of PD activity under operational conditions. Modern online monitoring systems track PD signals and gas formation trends, helping prevent unexpected failures. 4. Maintenance Practices Use partial discharge testers for periodic assessments, especially for transformers rated above 110 kV. Conduct repairs or retrofitting as needed to mitigate weak points identified during testing. 5. Standards and Regular Maintenance Follow international standards (e.g., IEC 60270) for PD testing and monitoring. Implement regular maintenance cycles to inspect and clean insulation surfaces, ensuring optimal performance. Conclusion Partial discharge is a critical factor in the degradation of high-voltage electrical equipment, directly impacting reliability and safety. Understanding its causes, impacts, and solutions is essential for effective insulation management. Through rigorous testing, advanced monitoring, and proper maintenance, engineers can mitigate the risks posed by PD, ensuring long-term performance and reliability of power systems.

Vacuum oil purifiers are essential equipment in oil processing industries, designed to improve oil quality by removing impurities, water, and gases. Proper maintenance during shutdown and effective troubleshooting are critical to ensure the purifier operates efficiently and reliably. This article outlines the key maintenance procedures and analyzes common issues faced during operation, providing valuable insights for new engineers and procurement professionals. Shutdown Maintenance of Vacuum Oil Purifiers Proper shutdown procedures are crucial to prevent equipment damage and maintain operational efficiency. Below are the steps to follow when halting the operation of a vacuum oil purifier: Delay Stopping the Oil Pump: After disconnecting the heating power, allow the system to cool for at least 5 minutes before stopping the oil pump. Reason: This prevents thermal decomposition of oil residue in the circuit, which could produce hydrocarbon gases and damage the system. Drain Stored Water After Outdoor Use: If the equipment has operated in low-temperature environments, ensure that stored water in the vacuum pump and condenser is completely drained. Reason: Residual water can freeze in cold conditions, leading to damage to critical components. Regular Cleaning of the Condenser and Heater: Clean the condenser and heater components routinely to maintain their efficiency and extend their service life. Impact of Neglect: Accumulated debris or residue reduces heat transfer efficiency and may lead to overheating or equipment wear. Common Problems and Solutions in Vacuum Oil Purifiers Despite regular maintenance, vacuum oil purifiers may encounter operational challenges. Here are the most frequent issues and their resolutions: 1. Damaged Filter Plates Damaged filter plates are a prevalent issue in box-type oil filters. The following factors should be analyzed when multiple filter plates fail: Manufacturing Quality: Ensure that the filter plates meet quality standards and are constructed from durable materials compatible with the system's operating conditions. Raw Material Compatibility: Verify that the raw materials of the filter plates are compatible with the head pressure of the feeding pump to avoid excessive wear. Bar Pressing Method: Examine the quantity and quality of the bar plates and the processing precision of internal steel linings. Pressure Imbalance: Damage can occur when the pressure on both sides of a filter plate is uneven. Common causes include: Unbalanced Filtering Periods: One side filters while the other undergoes hydraulic compression, creating a damaging pressure differential. Uneven Residue Distribution: During unloading, varying amounts of residue on both sides of the plate can lead to stress imbalances. 2. Spraying Material Between Filter Plates Material leakage between filter plates is another common problem. The underlying causes and solutions include: Blocked Feed Holes: Check for blockages in the feed holes of the filter plates, as restricted flow can increase pressure and lead to material ejection. Solution: Regularly inspect and clear feed channels to ensure smooth operation. Extended Idle Periods: Prolonged pauses in the feeding process can lead to uneven cake formation or sedimentation within the filter chamber. Solution: Minimize downtime during the filtering process and restart promptly after interruptions. Filter Cake Sinking: Uneven settling of the filter cake can occur if the feeding pump is stopped for extended periods. Solution: Monitor feeding intervals and ensure consistent material flow to maintain balanced pressure. Best Practices for Maintenance and Operation Preventive Maintenance: Schedule regular inspections of key components such as vacuum pumps, heaters, and filter plates. Replace worn parts promptly to prevent system failures. Proper Storage: When not in use, store the purifier in a cool, dry location to prevent corrosion or environmental damage. Training and Supervision: Ensure operators are trained in proper handling and maintenance practices to reduce the likelihood of operational errors. Timely Communication: Encourage open communication between operators and engineers to address issues promptly and implement corrective actions effectively. Conclusion By following the outlined maintenance procedures and addressing common operational issues, vacuum oil purifiers can achieve optimal performance and longevity. For new engineers and procurement professionals, understanding these aspects ensures informed decisions, efficient operation, and reduced downtime in oil filtration processes.

AC/DC voltage dividers, often referred to as digital high-voltage meters, are essential tools for measuring high voltage in power systems with accuracy and reliability. Proper usage is critical for ensuring precise measurements and maintaining operator safety. The following guidelines provide a detailed explanation for new engineers and procurement professionals to understand the best practices and precautions when using these devices. Precautions for Using AC/DC Voltage Dividers 1. Keep the Surrounding Area Clean Why It Matters: Debris or foreign objects around the equipment can interfere with the electric field, leading to inaccurate measurements. Best Practice: Always ensure the measurement area is clear of dust, conductive materials, and unnecessary objects before starting the operation. 2. Maintain a Safe Operating Distance Why It Matters: High-voltage measurement involves significant safety risks. Maintaining the proper distance reduces the risk of accidental contact or electric shock. Best Practice: Use insulated tools and follow the manufacturer’s recommended safety distance to avoid unsafe proximity to live equipment. 3. Verify Connection Reliability Why It Matters: Loose connections, especially in the grounding system, can compromise measurement accuracy and create safety hazards. Best Practice: Inspect all connections thoroughly before powering up the device. Ensure the ground wire is securely and firmly connected to a proper grounding point. 4. Confirm Zero Voltage Before Approaching Why It Matters: After completing the measurement, residual voltage may remain in the system, posing a risk of electric shock. Best Practice: Enter the testing area only when the instrument display indicates zero voltage. Wait an appropriate time to ensure discharge. 5. Avoid Overpressure and Keep the Surface Clean Why It Matters: Operating the device under excessive pressure can damage the internal components and compromise its accuracy. A clean surface ensures optimal insulation and reduces the risk of tracking or arcing. Best Practice: Always operate within the voltage and pressure limits specified by the manufacturer. Regularly clean the device’s surface using a soft, non-abrasive cloth to remove dirt or contaminants. Store the equipment in a cool, dry place to prevent environmental damage when not in use. 6. Handle with Care Why It Matters: Voltage dividers are precision instruments that can be easily damaged by physical impacts, compression, or improper handling. Best Practice: Transport the device in its designated protective case to prevent physical damage. Avoid dropping, colliding, or stacking heavy objects on the equipment. Additional Tips for New Engineers Pre-Use Calibration: Ensure the voltage divider is properly calibrated according to industry standards before use. Regular calibration maintains accuracy over time. Environmental Considerations: Avoid using the device in high-humidity or dusty environments, which can affect insulation properties and measurement accuracy. Understand the Measurement Range: Familiarize yourself with the voltage range and resolution of the voltage divider to ensure it is suitable for the application at hand. Emergency Preparedness: Train on emergency procedures, such as disconnecting power and using appropriate fire extinguishers, in case of unexpected incidents. Conclusion By following these precautions, new engineers and procurement professionals can ensure the safe and effective use of AC/DC voltage dividers (digital high-voltage meters). These guidelines not only help in achieving accurate measurements but also mitigate risks associated with high-voltage testing, safeguarding both personnel and equipment.

Gas chromatography for dissolved gas analysis (DGA) in transformer oil is an essential diagnostic tool for evaluating the health and reliability of transformers. This article provides a detailed guide to the testing cycle and standards for performing gas chromatography on transformer oil, aimed at helping new engineers and procurement professionals understand its importance and execution. Importance of Dissolved Gas Analysis (DGA) DGA measures the concentrations of gases dissolved in transformer oil, which are generated as a byproduct of thermal and electrical stress inside transformers. By analyzing these gases, engineers can: Detect early faults such as overheating, partial discharges, or arcing. Monitor operational conditions to ensure transformer reliability. Plan maintenance to prevent catastrophic failures. Key gases monitored include hydrogen (H2), methane (CH4), acetylene (C2H2), ethylene (C2H4), and carbon monoxide (CO). Testing Cycle for Dissolved Gas Analysis The frequency of DGA testing depends on the voltage rating, capacity, and operational conditions of the transformer. Below are the recommended cycles for various transformer types: 220 kV Transformers and Above 120 MVA Transformers: Test every 3-6 months during normal operation. Additional tests on the 4th, 10th, and 30th days after installation, overhaul, or winding replacement. 110 kV Transformers: Test once every 30 days and 180 days after installation, overhaul, or winding replacement. Subsequently, test annually. 35 kV Transformers: Transformers rated 8 MVA and above: Test annually. Transformers rated below 8 MVA: Test annually. Ad-hoc Testing: Perform tests when abnormal operational conditions arise, such as unexplained temperature rises, load imbalances, or oil discoloration. Test Standards for Dissolved Gas Content To ensure transformers operate safely and reliably, the following standards must be adhered to when analyzing dissolved gas content in transformer oil: Newly Installed Transformers: Total Hydrocarbon Gases (THG): ≤ 20 μL/L Hydrogen (H2): ≤ 30 μL/L Acetylene (C2H2): Not detectable. Transformers After Major Maintenance: Total Hydrocarbon Gases (THG): ≤ 50 μL/L Hydrogen (H2): ≤ 50 μL/L Acetylene (C2H2): Trace amounts allowed. 110 kV and Above Transformers: If C2H2 is detected, the testing frequency should be increased to track trends and monitor the equipment's condition closely. Operating Transformers (Alert Thresholds): Total Hydrocarbon Gases (THG): ≥ 150 μL/L Hydrogen (H2): ≥ 150 μL/L Acetylene (C2H2): ≥ 5.0 μL/L Gas Production Rate: If the relative gas production rate exceeds 10% per month, it is an indication of abnormal operation. This applies to both open-type and sealed transformers. Key Principles of Gas Chromatography for DGA Gas chromatography separates and quantifies individual gases dissolved in transformer oil. Here are the steps and principles involved: Oil Sample Extraction: Oil samples are collected from the transformer under controlled conditions to prevent contamination or gas loss. Gas Extraction: Dissolved gases are extracted from the oil using vacuum or gas stripping methods. Chromatographic Analysis: Gases are passed through a column where they separate based on molecular size and polarity. A detector measures the concentration of each gas. Data Interpretation: Compare the measured gas concentrations to the standard thresholds to determine the condition of the transformer. Applications and Benefits Fault Diagnosis: Identifies specific fault types (e.g., thermal faults, electrical discharges) by analyzing the gas composition. Preventive Maintenance: Allows early detection of issues, reducing the likelihood of unplanned outages or expensive repairs. Regulatory Compliance: Ensures transformers meet operational and safety standards. Asset Management: Extends transformer life by identifying and addressing faults before they escalate. Conclusion Gas chromatography-based dissolved gas analysis is an indispensable practice for maintaining the health and safety of transformers. By adhering to the recommended testing cycles and standards, engineers and procurement professionals can ensure early fault detection, minimize downtime, and enhance the reliability of power systems. For new engineers and buyers, understanding these procedures provides a foundation for making informed decisions about transformer maintenance and diagnostics.

Introduction to SF6 Gas Leakage Hazards Sulfur hexafluoride (SF6) gas is extensively used as an insulation and arc-extinguishing medium in electrical power systems due to its superior dielectric properties. However, its leakage poses significant risks, making detection and management essential. The hazards of SF6 gas leakage include: Health Risks: SF6 is a heavy gas that displaces oxygen, potentially causing local hypoxia (oxygen deficiency) in confined spaces. Prolonged exposure to low-oxygen environments can lead to dizziness, unconsciousness, or even life-threatening conditions for workers. Equipment Damage: SF6 leakage diminishes the arc-extinguishing and insulation performance of electrical equipment such as circuit breakers and transformers. This degradation can result in equipment malfunction, reduced reliability, and costly downtime or repairs. Environmental Impact: SF6 is a potent greenhouse gas with a global warming potential (GWP) thousands of times greater than CO2. Uncontrolled leakage contributes significantly to environmental harm and regulatory non-compliance. How SF6 Gas Quantitative Leak Detectors Address These Issues The SF6 gas quantitative leak detector is a critical tool for maintaining safety and ensuring equipment reliability in power systems. It provides both qualitative and quantitative assessments of SF6 leakage, enabling precise and timely responses. Key benefits include: Accurate Leakage Detection: The device identifies leakage points with high sensitivity, even in complex equipment setups. Quantitative measurements allow users to assess the severity of the leak and prioritize repair efforts. Enhanced Safety: Early detection prevents workers from being exposed to hazardous conditions caused by local hypoxia. Quantitative data ensures that all safety risks are addressed comprehensively. Improved Equipment Reliability: By detecting and addressing leaks promptly, the detector helps maintain the arc-extinguishing and insulation performance of SF6-based equipment. This proactive maintenance minimizes unexpected breakdowns and extends equipment lifespan. Compliance with Environmental Regulations: Regular monitoring with SF6 leak detectors ensures compliance with environmental regulations regarding SF6 usage and emissions. Reducing SF6 emissions aligns with global sustainability goals and corporate responsibility initiatives. Applications of SF6 Gas Quantitative Leak Detectors SF6 gas leak detectors are indispensable in various scenarios within the power system industry. Their applications include: Medium and High Voltage Circuit Breakers: Ensures the integrity of SF6 insulation in circuit breakers, preventing arc faults and maintaining operational safety. Transformers and Substations: Monitors the condition of transformers and substation equipment, where SF6 is used as a primary insulation medium. Gas-Insulated Switchgear (GIS): Detects and quantifies leaks in enclosed systems where SF6 gas is used to ensure compact and efficient operation. Maintenance and Field Testing: Portable detectors are essential tools for on-site inspection, periodic maintenance, and emergency leak investigations. Supplementary Insights Working Principle of SF6 Leak Detectors: These devices employ advanced sensing technologies, such as infrared absorption or electrochemical sensors, to identify SF6 molecules in the air. The detector quantifies the concentration of SF6, providing precise data for decision-making. Choosing the Right Detector: Select devices with high sensitivity, rapid response times, and robust anti-interference capabilities for accurate measurements in harsh conditions. Ensure the detector meets industry standards and supports compliance with environmental and safety regulations. Maintenance Best Practices: Regularly calibrate detectors to maintain accuracy and reliability. Integrate periodic SF6 testing into maintenance schedules to ensure continuous monitoring. Conclusion The widespread use of SF6 gas in power equipment has made quantitative leak detection a fundamental practice for ensuring safety, maintaining equipment performance, and protecting the environment. For new engineers and procurement professionals, understanding the principles, benefits, and applications of SF6 gas quantitative leak detectors is essential for effective equipment management and safety assurance.

The dielectric loss tester plays a vital role in evaluating the insulation performance of electrical equipment and is widely used across the power industry. For new engineers and procurement professionals, understanding its application scenarios and principles is crucial for effective use and equipment selection. Below are key application fields and supplemental details for better comprehension. 1. Insulation Performance Evaluation for High-Voltage Equipment Dielectric loss testers are extensively used to assess insulation quality in equipment such as: Transformers Reactors Capacitors The dielectric loss factor (tan δ) is a critical parameter for evaluating the insulation integrity of these devices. A high dielectric loss factor often indicates insulation degradation caused by: Moisture ingress Contamination Aging of insulation materials By measuring this parameter, engineers can proactively identify potential issues and schedule maintenance to avoid failures. 2. Insulation Testing for Bushings and Lightning Arresters Bushings and lightning arresters are essential components of electrical systems that require reliable insulation. The dielectric loss factor provides key insights into their insulation performance by detecting: Partial discharges Moisture absorption Contaminant deposition Periodic testing ensures these devices remain operational under high-voltage stress, minimizing risks of electrical breakdown and improving system reliability. 3. High-Accuracy Testing in Electromagnetically Interfering Environments In substations and other environments with significant electromagnetic interference (EMI), dielectric loss testers are indispensable. Modern testers are equipped with: Advanced filtering capabilities: To eliminate noise and enhance accuracy. Stable performance in EMI environments: Ensures reliable measurements even in challenging conditions. This capability is particularly beneficial for monitoring insulation performance in critical systems where accuracy is paramount for operational safety. 4. Supplemental Applications and Benefits Predictive Maintenance: Dielectric loss measurements help in early detection of insulation defects, allowing for timely repairs and reducing unexpected downtime. Equipment Longevity: Regular testing ensures that insulation systems remain within optimal performance ranges, extending the service life of expensive electrical assets. Versatility: Suitable for both on-site and laboratory conditions, these testers are adaptable to diverse testing needs. Compliance with Standards: Dielectric loss testers help meet industry regulations such as IEC, IEEE, and national standards, ensuring quality and safety benchmarks. Principle of Dielectric Loss Testing The dielectric loss factor, or tan δ, represents the energy lost as heat in an insulating material when subjected to an alternating electric field. The tester applies a high AC voltage across the insulation and measures: Capacitance: Indicates the ability to store electrical energy. Dissipation factor (tan δ): Represents energy losses due to imperfect insulation. A low dielectric loss factor signifies good insulation performance, while higher values indicate potential issues requiring attention. Key Considerations for New Engineers and Buyers Test Equipment Features: Look for devices with high anti-interference capabilities and user-friendly interfaces for precise and efficient testing. Standards and Compliance: Ensure the tester conforms to relevant standards for your equipment. Routine Testing: Incorporate dielectric loss measurement into regular maintenance schedules to improve overall system reliability. This comprehensive understanding of dielectric loss testers equips new engineers and procurement professionals to make informed decisions, optimize equipment performance, and ensure operational safety in electrical systems.

Testing vacuum circuit breakers (VCBs) is a critical process to ensure their reliable operation, safety, and compliance with technical specifications. The following sections outline the key test items and methods, with detailed explanations tailored for new engineers or procurement professionals to understand the principles and procedures clearly. 1. Insulation Resistance Measurement Insulation resistance testing evaluates the integrity of the insulation materials, preventing electrical leakage or breakdown. The procedure involves: Overall Insulation Resistance: Refer to the manufacturer’s guidelines for acceptable values. Use a megohmmeter with an appropriate voltage range for testing. Insulation Rod Resistance: At room temperature, the resistance value should meet the specified requirements in the technical standards provided by the manufacturer. Deviations may indicate contamination, moisture ingress, or insulation aging. 2. Resistance Measurement of Each Phase Conductive Circuit The resistance of each phase conductive circuit reflects the quality of electrical connections and conductor materials. This is measured using the DC voltage drop method: Testing Current: Apply a current of at least 100A during the test to ensure accurate results. Assessment: Compare the measured values with the technical conditions specified for the product. Excessive resistance may indicate loose connections, corrosion, or substandard conductors. 3. AC Withstand Voltage Test This test evaluates the circuit breaker's ability to withstand high voltage without insulation failure or breakdown. It is performed under two states: Closed State: Apply the specified test voltage across the breaker in its closed position. The voltage level must comply with the values outlined in the manufacturer's table or technical standards. Open State: Test the vacuum interrupter (arc-extinguishing chamber) by applying the specified voltage across its contacts. Ensure no through discharge occurs during the test. This test is critical for detecting weaknesses in insulation and ensuring operational reliability under high voltage conditions. 4. Timing Tests for Opening and Closing Operations The operational timing of the circuit breaker is crucial for ensuring coordinated system protection. The following tests should be performed: Opening and Closing Time: Measure the time required for the main contacts to open and close under rated voltage and hydraulic pressure conditions. Verify compliance with the product’s technical specifications. Contact Bounce Time: Measure the duration of contact bounce during the closing process: For breakers rated below 40.5kV: Bounce time ≤ 2ms. For breakers rated 40.5kV and above: Bounce time ≤ 3ms. Excessive bounce can lead to contact wear, heating, and operational inconsistencies. Reproducibility: Ensure periodicity and consistency of the operation timing. 5. Testing Insulation Resistance and DC Resistance of Coils The opening and closing coils, as well as the contactor coils, must be tested for proper insulation and electrical characteristics: Insulation Resistance: Resistance should be ≥ 10MΩ to ensure effective insulation. DC Resistance: Measure and compare with factory-provided values. Significant deviations could indicate coil damage or manufacturing defects. 6. Operating Mechanism Test The mechanical integrity of the circuit breaker’s operating mechanism directly impacts its performance. This test includes: Verification of Mechanism Functions: Test for smooth operation of the mechanism, including spring charging, opening, and closing. Lubrication and Wear Check: Inspect moving parts for proper lubrication and check for signs of mechanical wear or misalignment. Compliance: Ensure all parameters align with the relevant technical standards and specifications. Supplementary Notes Why These Tests Are Important: Vacuum circuit breakers are critical for isolating electrical faults and protecting equipment. These tests ensure their performance, reliability, and safety. Recommended Equipment: Use calibrated and certified instruments to guarantee accuracy. For example: Insulation Resistance Test: Megohmmeter with appropriate voltage range. Resistance Test: Micro-ohmmeter or high-current DC resistance tester. Timing Test: Digital timing analyzer. Safety Precautions: Ensure proper grounding during tests to avoid accidental discharge. Follow safety protocols, such as wearing insulated gloves and using warning signs. Conclusion Performing these tests systematically ensures that vacuum circuit breakers meet operational and safety requirements. For new engineers and procurement professionals, understanding these procedures builds a foundation for selecting and maintaining high-quality equipment. By adhering to these test methods, you can guarantee the long-term reliability and performance of vacuum circuit breakers in electrical systems.

Testing vacuum circuit breakers (VCBs) is a critical process to ensure their reliable operation, safety, and compliance with technical specifications. The following sections outline the key test items and methods, with detailed explanations tailored for new engineers or procurement professionals to understand the principles and procedures clearly. 1. Insulation Resistance Measurement Insulation resistance testing evaluates the integrity of the insulation materials, preventing electrical leakage or breakdown. The procedure involves: Overall Insulation Resistance: Refer to the manufacturer’s guidelines for acceptable values. Use a megohmmeter with an appropriate voltage range for testing. Insulation Rod Resistance: At room temperature, the resistance value should meet the specified requirements in the technical standards provided by the manufacturer. Deviations may indicate contamination, moisture ingress, or insulation aging. 2. Resistance Measurement of Each Phase Conductive Circuit The resistance of each phase conductive circuit reflects the quality of electrical connections and conductor materials. This is measured using the DC voltage drop method: Testing Current: Apply a current of at least 100A during the test to ensure accurate results. Assessment: Compare the measured values with the technical conditions specified for the product. Excessive resistance may indicate loose connections, corrosion, or substandard conductors. 3. AC Withstand Voltage Test This test evaluates the circuit breaker's ability to withstand high voltage without insulation failure or breakdown. It is performed under two states: Closed State: Apply the specified test voltage across the breaker in its closed position. The voltage level must comply with the values outlined in the manufacturer's table or technical standards. Open State: Test the vacuum interrupter (arc-extinguishing chamber) by applying the specified voltage across its contacts. Ensure no through discharge occurs during the test. This test is critical for detecting weaknesses in insulation and ensuring operational reliability under high voltage conditions. 4. Timing Tests for Opening and Closing Operations The operational timing of the circuit breaker is crucial for ensuring coordinated system protection. The following tests should be performed: Opening and Closing Time: Measure the time required for the main contacts to open and close under rated voltage and hydraulic pressure conditions. Verify compliance with the product’s technical specifications. Contact Bounce Time: Measure the duration of contact bounce during the closing process: For breakers rated below 40.5kV: Bounce time ≤ 2ms. For breakers rated 40.5kV and above: Bounce time ≤ 3ms. Excessive bounce can lead to contact wear, heating, and operational inconsistencies. Reproducibility: Ensure periodicity and consistency of the operation timing. 5. Testing Insulation Resistance and DC Resistance of Coils The opening and closing coils, as well as the contactor coils, must be tested for proper insulation and electrical characteristics: Insulation Resistance: Resistance should be ≥ 10MΩ to ensure effective insulation. DC Resistance: Measure and compare with factory-provided values. Significant deviations could indicate coil damage or manufacturing defects. 6. Operating Mechanism Test The mechanical integrity of the circuit breaker’s operating mechanism directly impacts its performance. This test includes: Verification of Mechanism Functions: Test for smooth operation of the mechanism, including spring charging, opening, and closing. Lubrication and Wear Check: Inspect moving parts for proper lubrication and check for signs of mechanical wear or misalignment. Compliance: Ensure all parameters align with the relevant technical standards and specifications. Supplementary Notes Why These Tests Are Important: Vacuum circuit breakers are critical for isolating electrical faults and protecting equipment. These tests ensure their performance, reliability, and safety. Recommended Equipment: Use calibrated and certified instruments to guarantee accuracy. For example: Insulation Resistance Test: Megohmmeter with appropriate voltage range. Resistance Test: Micro-ohmmeter or high-current DC resistance tester. Timing Test: Digital timing analyzer. Safety Precautions: Ensure proper grounding during tests to avoid accidental discharge. Follow safety protocols, such as wearing insulated gloves and using warning signs. Conclusion Performing these tests systematically ensures that vacuum circuit breakers meet operational and safety requirements. For new engineers and procurement professionals, understanding these procedures builds a foundation for selecting and maintaining high-quality equipment. By adhering to these test methods, you can guarantee the long-term reliability and performance of vacuum circuit breakers in electrical systems.

The AC withstanding voltage test, also known as the AC dielectric test, is a critical test in electrical engineering used to evaluate the insulation strength of electrical equipment or components. It involves applying a high AC voltage to the test object to verify its ability to withstand voltage stress without insulation breakdown. Here’s a detailed explanation: Purpose Verify Insulation Integrity: Ensures that the insulation of cables, transformers, switchgear, and other electrical devices can handle operational and transient voltage stresses safely. Detect Weak Points: Identifies defects, weaknesses, or degradation in insulation materials before they lead to equipment failure. Compliance: Confirms adherence to safety and performance standards. Procedure Setup: The test object is connected to a test setup, typically consisting of a high-voltage AC source, voltage divider, and measuring instruments. The insulation is tested between its conductive parts (e.g., between live conductors and ground). Voltage Application: A specified high AC voltage is gradually applied to the test object. The test voltage is generally much higher than the normal operating voltage to simulate extreme conditions. Duration: The voltage is maintained for a specified duration (e.g., 1 minute) to check for insulation breakdown or excessive leakage current. Monitoring: Measurements of leakage current and visual or acoustic detection of partial discharges are often performed to assess the insulation performance. Pass/Fail Criteria: The test is considered successful if there is no breakdown, flashover, or excessive leakage current. Applications Power Cables: To test the dielectric strength of cable insulation. Transformers: To verify the insulation between windings and between windings and the core. Switchgear: To test the insulation between phases and between phase and ground. Generators and Motors: To ensure the winding insulation can handle the applied voltage stresses. Standards The test is governed by various international and national standards, such as: IEC 60060: High-voltage test techniques. IEEE 4: Techniques for high-voltage testing. Industry-specific standards like those for cables, transformers, and switchgear. Safety Considerations High Voltage Risks: Only trained personnel should conduct the test using appropriate safety measures. Grounding: Ensure the test setup is properly grounded. Personal Protective Equipment (PPE): Use insulated gloves, safety mats, and other protective gear. Discharge After Test: Properly discharge the test object to prevent residual voltage hazards. The AC withstanding voltage test is essential for ensuring the reliability, safety, and longevity of electrical systems and components.

Battery internal resistance is a critical parameter that directly impacts the performance, efficiency, and lifespan of batteries. Accurately measuring the internal resistance and open circuit voltage of a battery is essential for assessing its health and functionality. This guide will delve into the basic principles, testing methods, and considerations for engineers and procurement professionals to better understand and select appropriate testing methods and equipment for battery internal resistance. 1. Why Test Battery Internal Resistance and Open Circuit Voltage? Testing a battery’s internal resistance and open circuit voltage provides a quick and reliable means to assess the overall condition of the battery. These parameters are crucial indicators of a battery’s ability to perform under load and how well it holds charge. Internal Resistance: The internal resistance of a battery reflects its ability to resist the flow of electric current. High internal resistance leads to energy losses, reduced capacity, and poor performance under load. Open Circuit Voltage (OCV): The OCV provides information about the charge level of the battery when it is not under load. A drop in OCV often signifies reduced capacity or potential battery failure. By testing both of these parameters, it’s possible to detect issues early and prevent failures in critical applications. 2. Common Methods for Testing Battery Internal Resistance Two widely used methods for testing battery internal resistance are based on different measurement techniques and principles: AC Injection Method: This method involves applying an alternating current (AC) signal to the battery and measuring its impedance at a specific frequency. It is commonly used for testing batteries like lithium-ion batteries, which are sensitive to voltage fluctuations and require precise resistance measurements. DC Discharge Method: In this method, a direct current (DC) load is applied to the battery, and the voltage drop is measured over time. This method is often used in situations where accurate load testing is necessary to assess how well the battery can perform under real-world conditions. Both methods are effective for evaluating battery performance, but their applicability depends on the specific type of battery and the intended use of the measurement. 3. Principles Behind AC Internal Resistance Testing The AC internal resistance method operates on the principle of impedance spectroscopy. It measures the battery’s vector impedance by applying a small AC signal and analyzing the voltage and current response at a set frequency. This method provides more accurate and detailed insights into the battery’s behavior at different operating conditions. Impedance Model: The AC method relies on an impedance model that includes both resistive and reactive components (capacitive and inductive). By analyzing these components, engineers can gain a better understanding of how the battery will perform in various electrical systems. Communication Resistance: Communication resistance refers to the equivalent resistance of the battery’s impedance when represented in the vector plane. This helps engineers interpret how the battery will behave in practical applications, particularly in communication systems or power electronics. 4. Comparing AC and DC Testing Methods Although both methods assess battery performance, they do so based on different models and approaches. Here's a comparison: AC Method: The AC method is preferred for lithium batteries and other sensitive chemistries, as it provides more detailed impedance data, which is crucial for understanding how the battery reacts under varying frequencies. DC Method: The DC discharge method is typically used for high-capacity batteries or applications where real-world load testing is required, such as in power storage systems. In summary, while both methods are effective, the AC method is generally the go-to choice for testing lithium-ion batteries, due to its higher accuracy in detecting internal resistance at the micro-ohm level. 5. Typical Frequency for Communication Resistance Testing For communication resistance testing, the commonly used testing frequency is 1 kHz. This frequency is optimal for assessing the dynamic behavior of most battery types under typical operating conditions. Higher frequencies are often used for precise measurements in specialized applications, such as RF circuits and advanced power systems. 6. Equipment for Testing DC Resistance To test DC resistance, a DC electronic load tester equipped with battery internal resistance measurement capabilities is required. These testers are designed to apply a constant DC load to the battery and measure the corresponding voltage drop, which can be used to calculate the internal resistance. When choosing equipment, it's essential to consider the test load range and accuracy to ensure reliable results, especially for high-capacity batteries or critical applications. 7. Impact of Eddy Currents on Testing Accuracy Eddy currents can interfere with the accuracy of internal resistance testing, especially in high-frequency AC measurements. These currents can create localized magnetic fields that may alter the voltage response, leading to incorrect measurements. Conditions for Eddy Currents to Occur: Presence of metallic surfaces near the loop plane (less than 10 cm) Metallic material inside the testing loop Impact on Testing Accuracy: Eddy currents can lead to a reduction in test accuracy by causing current bypass and distorting the results. Engineers should ensure that the testing environment is free from metal objects that may generate these unwanted currents. 8. Why Use the Four-Probe Method? The four-terminal or four-probe method is used for accurate measurement of battery internal resistance, particularly for those at the milli-ohm and micro-ohm levels. This method minimizes the impact of contact resistance by using separate paths for current and voltage measurements, ensuring more precise results. Dual Probe Limitations: While a dual-probe method is sufficient for basic impedance measurements at the Ω level, it does not provide the sensitivity required for measuring mΩ-level resistances, which are typical for battery testing. Conclusion: Technical and Procurement Insights For engineers and procurement teams, understanding the methods and equipment for testing battery internal resistance is crucial for ensuring optimal battery performance and longevity. The AC injection method is commonly preferred for lithium-ion batteries and other advanced chemistries, as it offers high accuracy at low resistance levels. The DC discharge method is better suited for high-capacity batteries and practical load testing. When selecting equipment, consider factors such as measurement accuracy, frequency response, and compatibility with battery types. Additionally, understanding the potential impact of eddy currents and using the four-probe method for precise testing will help ensure reliable and accurate measurements. By incorporating these considerations into your testing strategy, you can better assess the health of batteries and make informed decisions for both technical development and procurement processes.