Transformer partial discharge online monitoring system manufacturers

What is transformer partial discharge online monitoring system?

Transformer Partial Discharge Online Monitoring System (Transformer Partial Discharge Online Monitoring System) is a kind of intelligent equipment system for all-weather, non-invasive real-time monitoring of power transformer insulation status. Partial Discharge (Partial Discharge, referred to as PD) refers to the transformer insulation medium in the high-voltage electric field under the action of the local breakdown discharge phenomenon, is the insulation aging, defects in the early signs of deterioration. If not detected in time, partial discharge will continue to erode the insulation material, ultimately leading to transformer insulation breakdown, power failure and even equipment scrap.

The traditional offline detection method relies on regular outage test, unable to grasp the discharge law of transformer in real load operation state, there is an obvious detection blind spot. Transformer partial discharge online monitoring system through online, continuous, real-time collection of local discharge signal, with the background software intelligent analysis, to realize the transformer insulation health state of the whole life cycle management, is the modern power equipment condition maintenance (CBM) one of the core technical means.

Transformer partial discharge online monitoring system core components detailed explanation

A complete transformer partial discharge online monitoring system consists of the following three core modules, each module works together to form a complete closed loop from signal acquisition, data processing to visualization and analysis.

1. Local discharge on-line monitoring receiver

The receiving host is the computing core of the whole system. It is responsible for receiving the original signals from various types of local discharge sensors, completing signal conditioning, buffer isolation, bandpass filtering and signal amplification, and finally completing the digital acquisition with a high-speed sampling rate of 200MS/s. The host supports 4-channel or 6-channel flexible configuration, which can process multiple sensor data synchronously to meet the needs of large transformer multi-point monitoring. The host supports 4-channel or 6-channel flexible configuration, can synchronize the processing of multi-channel sensor data, to meet the needs of large transformer multi-point monitoring. The equipment adopts standard 2U model (483mm×89mm×300mm), which can be directly installed in the monitoring convergence cabinet or screen cabinet panel, convenient for centralized deployment and operation and maintenance management. The working power supply is adapted to AC 90～240V wide-voltage input, which has good adaptability to the site.

2. Multiple types of partial discharge sensors

Sensors are the front end of the system to sense the localized signals. The system adopts a sensor fusion scheme with three physical mechanisms: ultrasonic, high-frequency current and ultra-high-frequency, covering a wide bandwidth of detection from 20kHz to 3000MHz, ensuring that different types of localized defects in different locations can be effectively captured (see the comparison in the following section for details).

3. On-line local discharge monitoring back-office software system

The background software is deployed in the monitoring computer of the main control room, which is the core platform for data analysis and decision support. The software takes three-dimensional PRPD (Phase Resolved Partial Discharge) and PRPS (Phase Resolved Pulse Sequence) maps as the core display means, which visually presents the discharge amplitude, discharge phase and the distribution pattern of discharge times of the local discharge signals. Combined with the built-in expert database, the software can intelligently compare common discharge modes (air gap discharge, discharge along the surface, suspended potential, etc.) with the initial judgment of fault types, significantly reducing the threshold of professional analysis and helping operation and maintenance personnel to quickly make maintenance decisions.

Comprehensive Comparison of Three Sensor Types for Transformer Partial Discharge

Sensor selection directly determines the coverage and detection sensitivity of the monitoring system. The following is a detailed comparison of the three core sensors: ultrasonic discharge sensor, high-frequency current discharge sensor, and oil valve special high-frequency discharge sensor, to help users configure the optimal solution according to their needs.

Ultrasonic localized emission sensors (AE sensors)

Ultrasonic sensor monitoring bandwidth of 20kHz ~ 200kHz, the use of partial discharge generated by the mechanical vibration of the acoustic wave for non-electricity detection, electromagnetic interference has a natural anti-interference ability. Adopting magnetic suction type installation method, it is arranged on the outer wall around the transformer tank, through applying coupling agent at the bottom and closely adhering to the surface of the equipment, it can effectively monitor the local discharge signal of the high-voltage coil inside the tank. The sensor is easy to install, no need to change the primary equipment, especially suitable for the rapid retrofitting of in-service transformers.

High Frequency Current Local Discharge Sensors (HFCT Sensors)

The HFCT sensor has a monitoring bandwidth of 100kHz to 50MHz and is specifically designed to monitor high frequency impulse current signals generated by partial discharges. Adopting snap type installation, set on the transformer core grounding wire, non-invasive induction detection of impulse current in the core grounding cable.HFCT sensor has high sensitivity, transmission impedance of not less than 12mV/mA, and strong responsiveness to early weak discharges triggered by internal insulation defects, and it is one of the most widely used types of sensors in transformer partial discharge charged detection.

Oil Valve UHF Local Discharge Sensor (UHF Sensor)

UHF sensor monitoring bandwidth of 300MHz~3000MHz, working in UHF band, can effectively avoid the industrial frequency and its harmonic interference, in the complex electromagnetic environment of the substation has outstanding anti-interference advantages. The sensor adopts plug-and-play structure, and the active probe is extended into the internal insulating oil of the transformer through the outlet valve of the transformer, which directly senses the localized electromagnetic wave in the oil medium, and makes a more direct and accurate assessment of the internal insulating condition of the transformer. The monitoring range of this program can reach 20000pC, which is a high-precision means of evaluating the insulation operation status of large main transformers.

Transformer partial discharge online monitoring device manufacturers core technical advantages

As a professional manufacturer of transformer partial discharge online monitoring system, we have the following core technical competitiveness in product development and manufacturing level:

• Multi-sensor fusion monitoring technologyThe three physical mechanisms of ultrasonic, high-frequency current and ultra-high frequency work together, covering frequencies from 20kHz to 3GHz, comprehensively sensing localized signals from different dimensions, significantly improving detection coverage and accuracy, and making up for the blind spots of a single sensor technology.
• High-speed multi-channel synchronized acquisitionSampling rate up to 200MS/s, support 4/6 channels synchronous acquisition, channel consistency better than 0.5dBm, to ensure that the multi-point signal timing alignment, for the localization and analysis of the source of localized discharge to provide a reliable data base.
• Intelligent anti-jamming circuit designSpecial design anti-interference circuit, dynamic range of -80 ~ -20dBm, effectively inhibit the substation site of the industrial frequency interference, radio interference and corona interference, to protect the system in the complex electromagnetic environment, stable and reliable operation.
• Industrial grade IP68 fully sealed protectionThe sensors and key components have reached IP68 protection level, which can work continuously for a long time in outdoor, high humidity, high dust and other harsh working conditions, and have excellent environmental tolerance ability.
• 3D mapping and expert intelligent diagnosis: The backend software has a built-in discharge pattern expert database, which, combined with PRPD/PRPS 3D visualization mapping, realizes intelligent auxiliary diagnosis of common defect types such as air-gap discharge, insulation aging, and metal levitation, and improves the efficiency of on-site operation and maintenance.
• Flexible communication and remote accessIt is equipped with RJ45 network port and RS485 interface as standard, which supports centralized collection, remote transmission and uploading to the backend cloud platform of bureau discharge monitoring data, and seamlessly integrates into the Internet of Things (IoT) and intelligent operation and maintenance (AISM) system of electric power.

Transformer partial discharge online monitoring system main function details

The system functions cover the whole chain of real-time monitoring, data storage, intelligent warning and historical analysis, meeting the needs of power operation and maintenance personnel for the whole scenario of equipment status perception.

Real-time localized status monitoring

The system continuously monitors and stores the average discharge amplitude, peak discharge amplitude, discharge phase, number of discharges and other key parameters of the transformer partial discharge, and synchronously generates 3D spectrograms of the local discharge signals (PRPD/PRPS spectrograms), so that operation and maintenance personnel can grasp the dynamics of the insulation status of the transformer in real time in the backstage interface, and obtain the "health checkup report" of the equipment without the need for power outages.

Intelligent Alarm and Early Warning Management

The system supports customized setting of multi-level alarm thresholds, and automatically triggers a graded warning (alert, attention, danger) when the amount of authority discharge exceeds the preset warning value, and prompts operation and maintenance personnel to intervene in a timely manner through the system interface to deal with the system interface, effectively preventing insulation defects from expanding into a sudden failure and blackout events.

Historical data query and trend analysis

The system has perfect historical data storage and retrospective function, supports the query of any historical period of local discharge monitoring data curve by time dimension, and provides statistical analysis and trend analysis function, helps operation and maintenance personnel to study and judge the rate of insulation deterioration of transformer, and provides data support for the formulation of maintenance plan.

Parameter Configuration and Device Management

The system provides a friendly parameter setting interface, supporting the entry of basic equipment information, sensor channel configuration, sampling parameter adjustment, alarm threshold programming and other operations, to meet the personalized monitoring needs of transformers of different capacities and voltage levels, and to facilitate the unified management of multiple devices.

Transformer partial discharge online monitoring system applicable scenes and application areas

This system is widely used in the condition overhaul and preventive maintenance scenarios of all types of high-voltage and ultra-high-voltage oil-immersed transformers, with specific application areas including:

• Grid substations: 110kV, 220kV, 500kV main transformer local line monitoring, supporting the construction of the grid company's condition maintenance work system.
• power plants: Long-term tracking and monitoring of the insulation status of plant transformers and main transformers to ensure the safe and stable operation of generating units.
• Industrial power distribution systems: Health status management of important distribution transformers in high energy-consuming industries such as iron and steel, petrochemical, and nonferrous metals.
• rapid transit: Localized on-line monitoring of traction transformers in urban subways and high-speed railroads to ensure the reliability of power supply in rail transportation.
• Data centers and large campuses: In locations where continuity of power supply is critical, unplanned outages can be avoided by detecting insulation hazards in advance through local line monitoring.
• New Energy Grid Connection Project: Insulation health management of step-up transformers in wind power and photovoltaic aggregation stations, adapting to the operation and maintenance needs of new energy power systems.

How to choose transformer partial discharge online monitoring device? Professional Selection Guide

In the face of a wide range of local release monitoring devices on the market, the following selection points can help purchasing decision makers to make a more scientific and reasonable choice:

Selection of sensors according to the voltage level of the equipment to be measured

110kV and below transformers are recommended to be high frequency current sensor (HFCT) based, supplemented by ultrasonic sensors; 220kV and above large main transformers are recommended to be deployed in combination of the three sensors, to give full play to the advantages of multi-source data fusion, and to enhance the comprehensiveness and reliability of the detection.

Focus on sample rate and channel count configurations

The local discharge signal is characterized by short pulse time and high frequency, and insufficient sampling rate will lead to signal distortion or even leakage detection. It is recommended to prioritize the use of sampling rate of not less than 200MS / s equipment; at the same time, according to the number of sensors on the site to choose 4-channel or 6-channel configuration, to avoid the lack of channels caused by the signal merger misjudgment.

Examination of anti-interference performance indicators

Substation site electromagnetic environment is complex, anti-interference ability is a measure of the core indicators of the practicality of the local discharge monitoring device engineering. Should focus on the examination of the dynamic range of the equipment (recommended not less than 60dB) and manufacturers of industrial frequency, harmonics, radio and other sources of interference for the specific suppression program.

Evaluate manufacturers' R&D and customization capabilities

Priority is given to manufacturers with independent research and development capabilities, who can provide customized solutions for sensor types, channel numbers and communication protocols according to special application scenarios, and provide perfect technical support and after-sales service to ensure long-term stable operation of the system.

Verify product qualification and protection level certification

Confirm whether the product meets the IP68 protection level (sensor part), and whether it has passed the relevant industry testing and certification, to ensure that the reliability of the equipment in outdoor and harsh working conditions meets the engineering requirements.

Why choose us--Specialized manufacturer of transformer partial discharge monitoring system

Inotera (Fuzhou) Sales Co., Ltd. focuses on the research and development and production of transformer online monitoring system and ancillary equipment, is a collection of independent research and development, large-scale manufacturing, technology customization in one of the professional manufacturers, in the field of transformer partial discharge online monitoring has accumulated a wealth of practical experience in the field of engineering.

• Manufacturer direct supply: Self-constructed production system, eliminating intermediate circulation links, providing customers with highly competitive ex-factory prices and reducing project procurement costs.
• Independent R&D StrengthThe core sensor technology and monitoring hosts are all self-developed, with key technology patents, rapid product iteration, and continuous optimization and upgrading according to customer needs.
• Customized Solutions: It supports multi-dimensional customization such as sensor combination, number of channels, communication protocols, software interface, etc. to meet the differentiated needs of different industries and scenarios.
• Genuine Quality AssuranceThe entire product line is subjected to strict factory inspection and a complete product quality traceability system is provided to ensure that each system is delivered in accordance with the design specifications.
• Professional Technical SupportProvide installation and commissioning guidance, operation training and long-term after-sales technical services to help users quickly master the system operation and give full play to the monitoring value of the equipment.

For detailed technical information, product quotation or customized solutions of transformer partial discharge online monitoring system, welcome to contact us through the official website, the professional technical team will provide you with support at the first time.

Frequently Asked Questions (FAQ) of Transformer Partial Discharge Online Monitoring System

Q1：What is the difference between transformer partial discharge online monitoring system and offline local discharge test?

Offline local discharge test needs to be applied in the laboratory or on-site test voltage for testing after transformer power failure, which cannot reflect the insulation state of transformer under real running load, and there are problems of long testing period and lag in finding defects. Online monitoring system in the transformer under normal operating conditions, continuous collection of local discharge data, can grasp the real-time insulation deterioration trend, to achieve early warning of faults, is the technical basis of the state maintenance mode.

Q2: Can the system monitor multiple transformers at the same time?

Can. The background monitoring software supports multi-device networking access, through the RJ45 network interface will be more than one local discharge monitoring host access to the same monitoring platform, to achieve the centralized and unified management and comparative analysis of the state of the local discharge of multiple transformers, suitable for substations, industrial parks, and other multi-transformer places of the scale of the deployment.

Q3: Can the system operate stably in a substation environment with strong interference?

The system is specially configured with anti-interference circuitry with a dynamic range of -80 to -20dBm, which can effectively suppress the common industrial frequency interference, corona discharge interference and wireless communication interference in substation sites. The sensor reaches IP68 protection level, adapting to high temperature, high humidity, high dust and other harsh field environments, and has been verified in many 110kV to 500kV substation projects for long-term stable operation performance.

Q4: How to install the transformer partial discharge monitoring system? Does it require a power outage?

Ultrasonic sensors are magnetically mounted on the outer wall of the tank, and high-frequency current sensors are clipped to the grounding wire, all of which can be installed without power outage, realizing the true meaning of non-stop electric power installation. The oil valve special high-frequency sensor needs to be inserted through the oil valve port, and the valve operation safety conditions need to be confirmed before installation. Monitoring host installed in the convergence cabinet or screen cabinet, the overall construction cycle is short, the normal operation of the power system has minimal impact.

Q5: What do PRPD mapping and PRPS mapping mean respectively?

PRPD (Phase-Resolved Partial Discharge) mapping takes the phase of industrial frequency as the horizontal axis and the discharge amplitude as the vertical axis, and forms the scatter distribution map with characteristic patterns through the superposition statistics of a large number of discharge pulses, which is the core analytical tool for the identification of the type of local discharge and the diagnosis of defects.PRPS (Phase-Resolved Pulse Sequence) mapping introduces the time dimension on the basis of the PRPD to form a three-dimensional dynamic display, which can reflect the evolution pattern of local discharge signals over time more intuitively, helping to determine the development and urgency of the defects. PRPS (Phase Resolved Pulse Sequence) mapping introduces the time dimension on the basis of PRPD to form a three-dimensional dynamic display, which can more intuitively reflect the evolution of the localized discharge signal over time, and help to judge the development and urgency of the defect.