Lightning arrester online monitoring wireless data transmission version (Bluetooth) BLQ-WX
1、 Preface
In recent years, in order to reduce the overvoltage caused by lightning strikes on transmission lines in mountainous areas, high-voltage transmission line lightning arresters have played a huge role and have been widely used. The performance of MOA lightning arresters directly affects the safe operation of power systems. Due to the long-term exposure to high power frequency voltage, MOA lightning arresters will gradually age and may experience breakdown damage during operation, resulting in a decrease in protection characteristics and extremely serious consequences. To ensure the safe operation of MOA lightning arresters, strict monitoring must be carried out.
At present, the method of monitoring MOA lightning arresters uses lightning arrester monitors to achieve online monitoring. Its working principle is that under normal operating voltage, the change in leakage current of the lightning arrester is measured by an ammeter. When a strong action current flows, it will be transferred from the leakage current measurement circuit to the counter circuit. The action of the counter uses the energy through the action current to record the number of actions. However, due to the remote location of mountainous transmission lines and the fact that lightning arrester monitors are installed at high tower heights, it is difficult to meter and maintain lightning arrester parameters. The current method is to use regular rotation of lightning arresters and conduct tower inspections and cleaning of lightning arresters and grounding devices during the annual standard maintenance. This method has high replacement costs for lightning arresters, high labor intensity, and requires a long power outage period, which is not conducive to the economic and stable operation of transmission lines. Therefore, a monitoring method that is "online, real-time, remote, intelligent, and reliable" must be adopted.
2、 System Overview
The wireless data transmission version lightning arrester online monitoring system (hereinafter referred to as this system) is a high-tech new product developed by our company for the needs of the power system. The current detection of this system adopts a single turn through core current sensor, achieving a fully isolated and residual voltage free sampling method. Advanced microprocessor technology and unique transient parameter testing technology are used for linearization processing and calculation, and the measurement results are transmitted digitally over a long distance through the Lora data transmission module. This system has extremely high reliability, safety, and relatively low price, making it possible to install it in each group of MOA lightning arresters for real-time detection, achieving centralized monitoring and effectively improving the inspection efficiency of line lightning arresters and reducing the labor intensity of inspection personnel. To accurately and timely grasp the health status of operating equipment, so that operators can timely grasp and deal with accident hazards in advance, and ensure the safe power supply of the power grid.
3、 Standards and specifications
DLT5149-2001 Technical Code for Design of Computer Monitoring System for 220-500kV Substation
JB/T10492-2004 Monitoring Sub for AC Metal Oxide Surge Arresters
JB2440-91 Discharge Counting for Surge Arrester
Q/GDW 393-2009 Design Specification for 110 (66) kV~220kV Intelligent Substation
4、 System features
1. Develop according to the Technical Regulations for Online Monitoring and Live Testing of Zinc Oxide Surge Arresters (Dian Sheng [2004] No. 338).
2. Non contact measurement principle: The current detection of this system uses non-contact measurement to achieve a fully isolated and residual voltage free sampling method, which does not have any impact on the operation of the lightning arrester, effectively ensuring personal safety and equipment safety.
3. Equipment does not require modification: The installation of this system does not require the removal of installed monitors and can operate simultaneously.
4. Outdoor structure, no leakage: The current transmitter adopts an aluminum alloy shell waterproof design, suitable for indoor and outdoor applications.
5. Effective anti-interference measures: The system has fully considered interference issues and adopted various effective anti-interference processing methods in hardware circuit and software design, ensuring the stable operation of the system and the stability of measurement data, which can meet the requirements for normal use in strong electromagnetic field interference environments.
6. Precise compensation and linear processing: This system adopts the most advanced design methods to linearize the detection signal and perform precise compensation to ensure the accuracy of the measurement data.
7. The monitor is powered by lithium batteries and solar charging. The lithium battery can last for more than 20 days in rainy weather to ensure the normal operation of the system.
8. Monitor information transmission: This system applies advanced Lora spread spectrum technology in the field of wireless data transmission, and can achieve long-distance data collection through a wireless gateway. The communication distance in open areas can reach 3km.
9. The gateway is connected to the mobile app via Bluetooth and sends the collected monitor data to the mobile app for display processing.
10. Alarm threshold: The alarm threshold setting of this system is mainly set in the mobile APP software.
5、 System functions and technical indicators
Overall System Structure Diagram
Lightning arrester status monitor gateway
Lightning arrester status monitor gateway
The lightning arrester online monitor has the function of detecting full current and lightning current, and sends the full current value and lightning record to the wireless gateway through the Lora spread spectrum module; Connect to the wireless gateway via Bluetooth through a mobile app to obtain lightning strike record data from the monitor.
The mobile app comes with a database data storage function, which collects and saves full current and lightning current data based on the device number of the lightning arrester online monitor. The data can be exported and shared with other devices on the mobile end.
(1) Main functions and technical requirements of lightning arrester online monitor
The main function of the lightning arrester online monitor is to achieve instantaneous detection and storage of lightning current, as well as full current detection. The power supply is powered by large capacity lithium batteries and solar charging, and the device can stand by for more than 15 days under no light conditions.
To ensure the battery level of the lightning arrester online monitor before leaving the factory, a power switch is installed on the installation panel. After the factory test, the power is turned off. When installing the equipment, the power is turned on and sealed with the prepared 704 silicone gel for waterproofing.
The lightning strike record data detected by the device is stored in the device, with a maximum storage of 400 records. If the clear storage command is not received, the stored data will be retained indefinitely. If the maximum number of records is exceeded, the old records will be automatically overwritten and the latest records will be retained.
The lightning arrester online monitor is usually in a sleep state. When it encounters lightning strikes or wireless communication with the gateway, it automatically wakes up. In the wake-up state, the device indicator light flashes every 1 second. When sending data to the gateway, the indicator light flashes rapidly. When the device is in sleep mode, the indicator light does not light up.
The records stored in the lightning arrester online monitor are collected by the wireless gateway through a 433MHz Lora spread spectrum module. The lightning strike records and full current data stored in the device are synchronized to the gateway and then read by the mobile app.
Main technical indicators:
☆ Detection of full current range: 0.05-5.00mA/RMS error ± 1% ± 2 words Minimum division: 10μA
☆ Number of lightning strike records stored: 0-400 times Accuracy: 100%
☆ Response value of discharge action count: 4/8 μ S ≥ 50A (peak)
☆ Work environment: for outdoor use- 25℃～60℃
☆ Detection of discharge current range: 50A~5KA/Peak error ± 10% Minimum division: 10 A
☆ Power supply: lithium battery+solar charging panel, safe and reliable.
☆ Work environment: for outdoor use- 40℃～50℃
☆ Transmission method: Wireless 433MHz Lora spread spectrum
(2) Main functions and technical requirements of lightning arrester wireless gateway
The wireless gateway for lightning arresters is mainly designed to cope with long-distance meter reading. The gateway communicates with the lightning arrester online monitor through a Lora spread spectrum module, and the effective communication distance can reach 3km under open conditions. Meet the vast majority of remote meter reading needs in the wild.
The gateway power supply is powered by a built-in lithium battery with a MicroUSB charging port, which can charge gateway devices through a 5V adapter or computer. The gateway is equipped with a power switch. When the device is turned off, press the power button for more than 0.5 seconds to turn it on. At this time, the running light will indicate the battery level, which is divided into 4 levels. Flashing 4 times indicates full charge, and so on. Flashing 1 time indicates low battery level. Long press the power button for 3 seconds to shut down the gateway, and the indicator light will not flash when turned off. The device will automatically shut down if there is no operation within 10 minutes.
The gateway is equipped with a Bluetooth interface, which can be connected via Bluetooth through a mobile app, and then connected to the lightning arrester online monitor through the gateway to achieve remote meter reading. The mobile app receives meter reading records and stores them in a local database, and supports export function to share the stored data with other networked devices. After the mobile phone is adapted to the gateway Bluetooth, the gateway Bluetooth indicator light will turn on, and the LORA indicator light will flash after synchronizing data. At this time, the device's recorded data can be read.
The mobile app is developed on the Android platform, and specific operation instructions can be found in the following chapters.
6、 User interface instructions for mobile APP software
1. Software installation
Installation platform requirements: Android system, Bluetooth 4.0 or above.
Click on the installation package to install the software.
2. Open the software
Click on the icon shown above on the screen to open the software.
Select Bluetooth devices for pairing
Gateway Bluetooth default name: BLQ_GW
3 Input lightning arrester status monitor number
The lightning arrester status monitor is divided into two parts: the partition block code and the intra area code. After entering the correct number, the gateway begins to synchronize data with the monitor with that number. When the gateway connection light flashes every 0.5 seconds, it indicates that the pairing is successful. At this time, the lightning strike records and other data of the monitor can be read.
Attention: When there are a large number of lightning strike records stored, the data synchronization process may take a long time, ranging from tens of seconds to over 1 minute.
4. Read record data
After completing device pairing, the mobile app interface enters the following interface, with four tabs at the bottom of the interface: "Discovery", "Communication", "Data", and "Settings". The "Discovery" tab enters the Bluetooth device discovery interface; The "Communication" tab is the current interface; The "Data" tab is used to view historical data and export data; The "Settings" tab is used for system parameter settings.
Under the "Communication" tab, which is the current interface, there are two buttons in the upper right corner: "Disconnect" and "Return". "Disconnect" is used to disconnect the Bluetooth connection, while "Return" is used to re pair the device. There are four buttons in the middle of the interface called "Read Times" to read device records; Clear device "is used to send wireless commands to clear the stored data of the lightning arrester monitor terminal; 'Clear Storage' is used to clear the local data in the mobile app database; Force Interruption "is used to interrupt the current communication when there is a communication error. The communication log contains connection information for each pass.
After completing device pairing, the gateway connection indicator lights up alternately before data reading can be performed. Click to read the number of times, prompt for record count, click OK to start reading data.
After completing the data reading, click on the data tab to perform record queries and perform operations such as data export and sharing.
5 Data Query and Parameter Setting
Current upper limit: When the full current exceeds the upper limit value, an alarm will be triggered, and the data will turn red as an alarm color
Current lower limit: If the full current is below the lower limit value, an alarm will be triggered, and the data will turn green as an alarm color
When the full current detection current is within the normal range, the data appears in blue.
