System Introduction
The PRE-STORM 2.0 atmospheric electric field meter is designed based on the grinding disc (or field grinding) principle, which obtains continuous measurement of changes in atmospheric electric field intensity through the continuous rotation of the motor. It consists of a stator (induction plate) and a rotor (grounding shielding plate). The rotor is driven to rotate by a motor with a constant speed of 1560 revolutions per minute, which alternately exposes the induction plate to the electric field or shields it, thereby generating induced charges proportional to the strength of the external electric field. The induction plate is connected to the amplification processing circuit and waveform adjustment circuit, and outputs a voltage signal. After calibration, this voltage can characterize the strength and polarity changes of the atmospheric electric field.
The PRE-STORM 2.0 atmospheric electric field meter is designed to meet the requirements of ground meteorological observation standards for measuring ground atmospheric electric field strength. This makes it also suitable for various other applications. The sturdy aluminum shell technology can withstand various harsh environments, and the inverted structure can effectively prevent the invasion of bird droppings, rainwater, fallen leaves, etc. At the same time, it also has the characteristics of low power consumption, easy installation, and simple maintenance, which can continuously measure changes in atmospheric electric field strength for a long time.
The most common application of the PRE-STORM 2.0 atmospheric electric field meter is for early warning of lightning. It is widely used in meteorological observation, environmental monitoring, petroleum and petrochemical industries, tourist attractions, golf courses, wind power generation, and large outdoor amusement parks.
Main performance indicators
working principle
The field grinding atmospheric electric field meter uses the principle of inducing charges on a conductor placed in an electric field to measure the strength and direction of the electric field.
The induced charge Q (t) on the stator in the electric field probe is a function of time, and its value is proportional to the external electric field strength E, as shown in formula (1).
Q(t)＝-ε0ES(t) .................................................... （1）
In the formula:
Q (t) - Induced charge on the stator of the electric field meter probe, measured in amperes (A);
ε 0- free space dielectric constant;
S (t) - The surface area of the stator exposed to an electric field, measured in square meters (m2).
So when the exposed area of the stator changes continuously over time, Q (t) is an alternating current signal. Due to the proportional relationship between electric field strength and induced current, the external electric field strength value can be obtained by measuring the equivalent voltage value generated by the induced current flowing through a large resistor. The proportional coefficient between the equivalent voltage value generated by the induced current flowing through a large resistor and the external electric field strength value can be obtained through calibration.
The measurement principle model is shown in Figure 2
The PRE-STORM 2.0 atmospheric electric field meter consists of hardware and software. The hardware can be divided into electric field induction probes, processing units, power supply units, communication control units, wireless transmission modules (optional), and peripheral components. Its software can be divided into two types: acquisition software and business software.
The logical structure of the device is shown in Figure 3.
Figure 3 Logic structure diagram of atmospheric electric field meter
In Figure 3, the atmospheric electric field instrument consists of an induction probe, a processing unit, and other components, supplemented by a communication control unit, a power supply unit, and peripheral components to form an independent atmospheric electric field observation station. The communication control unit can output data files to both local terminals and data centers through wireless networks.
Atmospheric electric field meter section
The atmospheric electric field instrument equipment consists of an induction probe and a processing unit.
The sensing component senses changes in the atmospheric electric field by inducing charges in the conductor, and converts them into measurable physical quantity signals.
The processing unit is a key component of the atmospheric electric field instrument. It consists of A/D conversion circuit, central processing unit, GPS clock, data storage, control circuit, and interface, as shown in Figure 4. Its main function is to measure the voltage signal output by the sensor, complete the A/D conversion of the sensor signal, sample the signal, and perform data processing, quality control, recording and storage on the sampled values to achieve data communication and transmission.
Communication control unit
The communication control unit is responsible for packaging, organizing, and verifying the observation data and warning status data of the atmospheric electric field instrument. It can send data according to pre-set communication methods and transmission time intervals, or adjust communication methods and transmission time intervals through remote commands.
When using wireless transmission modules, multi-point transmission can be achieved, and data can be sent to at least two data center stations simultaneously.
The communication control unit should also have input and output channels for analog and digital signals, which can realize changes in digital signals based on the warning information provided by the atmospheric electric field instrument, and can also receive analog and digital signals from other devices, and send data to the data center station through wireless modules.
2.3 Power Supply Unit
The power supply control unit is responsible for providing working power to the system, usually using a battery for power supply (DC 12V or 24V), and charging the battery with solar panels. If the conditions for mains power access are met, single-phase mains power 220V can also be used to charge the battery.
The power supply unit adopts current limiting protection and anti reverse connection measures to provide stable output current. Voltage conversion can be carried out according to requirements.
Peripheral components
Equipment installation brackets, sound and light alarm devices, etc. are collectively referred to as peripheral components.
Software
Collection software
The data acquisition software runs in the data processing unit of the atmospheric electric field instrument and has functions of data acquisition, data processing, data storage, and data transmission.
Business software
The business software is developed by the business supervisory unit for processing, displaying, storing, querying, and transmitting atmospheric electric field instrument observation data. It is an application software installed on the local terminal microcomputer or remote data center terminal. When the atmospheric electric field value reaches the alarm threshold, the software has sound and image alarm functions.
Installation environment requirements
Precautions before installation
(1) The electric field detection probe should be installed in a pollution-free environment;
(2) Avoid detecting smoke and various dust emitted by the engine near the probe (such as generator sets, railways, highways, etc. that are prone to dust);
(3) Avoid detecting probes near surfaces that are prone to static electricity (such as plastic storefronts, plastic platforms, etc.), and prioritize stone or concrete foundations;
(4) Do not install the detection probe near the lightning rod;
(5) In the case where the foundation is separated from the detection probe (such as in an unobstructed area where the detection probe is placed at the top of a pillar), the detection probe is fixed on a pillar at a height of 1.8 meters above the ground.
Selection of Surrounding Environment for Installing Detection Probes
When installing the detection probe at the top or near the building, there are certain restrictions on its installation position as it causes changes in the electric field intensity line. Therefore, it is necessary to avoid installing it at the base of objects with a certain height (trees, buildings, towers, etc.).
Here are several installation locations to choose from, with green representing areas or locations that can be installed and red representing areas or locations that cannot be installed.
Users can also choose to install the control box indoors (installation method shown in the figure below).
Produce foundation
Construction drawing of ground fixed foundation
Installation of atmospheric electric field meter
Equipment List
Tool List
Installation steps
(1) Fixing the support rod base to the cement foundation
List of materials used: M10 stainless steel nut, spring washer, gasket, each with 4, 17 wrenches.
(2) Fixing rod of control box and fixing of control box
List of materials used:
4 M8 stainless steel nuts, spring washers, and washers each;
12 wrenches, 1;
13 wrenches, 1;
4 black clamps (inside the accessory bag);
Four square gaskets (inside the accessory bag);
4 M6 * 80 screws and 4 spring washers each;
Two stainless steel connection brackets for the control box.
(3) Connection of sensors, probe cables, and control box fixed pipes
List of materials used:
1 set of inner hexagon;
Atmospheric electric field meter cable 4 * 0.5 2 meters each.
Step 1: Connect the probe to the four core cable
Step 2: Use an Allen tool to secure the probe to the circular tube
Step 3: As shown in the figure below, lead the four core cable of the probe to the control box
(4) Fixing of control box fixed pipe and basic components
List of materials used:
4 M8 stainless steel nuts;
13 wrenches and 1 wrench.
Pay attention to threading the power cord into the box.
(6) Cable connection
Connect the 3-core AC220 cable to the cement foundation and enter the control box through the second hole on the left side of the control box.
Insert the 4-core probe cable into the third hole on the left side of the control box.
Starting from the left, the wiring terminal sequence is as follows:
(7) Surface mount antenna
Attach the antenna to the top of the control box, with one end of the antenna entering the control box through the first hole on the left side and connecting to the communication module CCW4G01.
(8) Insertion of SIM
Line inspection
Finally, use a multimeter to check if the circuit is loose or incorrect. After passing the check, close the two air switches. The first switch from the left is the AC 220V incoming switch for the mains, and the second switch is the battery powered switch.
Insert the RJ45 Ethernet cable into the first RJ45 aviation plug from the left of the control box.
Under normal circumstances, the communication module CCW4G01 light indicates the following:
4.2 Communication module parameter settings
set up
Interface Description
Default parameters for communication module network port
Communication module setup steps
Support accessing addresses through a browser and directly configuring parameters. (Recommend using Chrome or Firefox browser)
Enter 192.168.3.127 to enter the settings interface
Click "OK" to enter the settings interface
Set a unique site number and modify the site number (change ZH1001 to N1001).
In RelayMode, select Alarm LED Mode/AutoSource Mode/HandSource Mode from the drop-down menu.
When selecting AutoSource Mode mode in RelayMode, you also need to select MoldedBreaker/MiniatureBreaker from the RelayType drop-down menu.
Set RelayShiftLevel to output the lowest lightning warning level, which defaults to 2.
Set RelayShiftTime and relay switching delay time.
Set GPRS SendCycle, set 4G transmission interval in milliseconds.
Dedicated APN users need to modify GPRSAccessPoint from CTLTE to a dedicated APN access point.
For example, the GPRSAccessPoint of Hainan Provincial Meteorological Bureau is hnqxj2. hq.
Set network port parameters, including IPv4, Subnet, Gateway.
Set the IP address and port of the data receiving server through LAN, ServerIP (LAN).
Set the IP address and port of the data receiving server via 4G, Server IP (GPRS).
Particular attention
For dedicated APN users, they also need to select GPRSAccessPonitEnable from the Command drop-down menu and click commit to submit.
After modifying all parameters, select 'save&Reboot' from the Command dropdown menu, click 'commit' to complete the setup.
Common calibration and calibration methods for field grinding atmospheric electric field instrument on site
Due to the uncertainty of outdoor observation environment, the ground type atmospheric electric field instrument will adsorb dust after running for a period of time. After cleaning and maintenance, it is necessary to calibrate and calibrate the probe on site. The reference method is shown in the following figure:
When using this method for on-site calibration, please pay attention to the following points:
⑴ Due to differences in the external design of equipment from various manufacturers, calibration reference values should be provided by the manufacturers. After completing the factory consistency measurement verification, the manufacturers should provide portable on-site calibration equipment and provide reference values;
⑵ The DC power supply of portable devices can be carried separately or taken from the on-site equipment, but the DC load needs to be grounded together with the probe to achieve the reference voltage;
⑶ Stainless steel circular plates should have the same center and radius as the sampling area; And the distance between the two is a fixed value.
General operating steps:
⑴ Power off the entire device and clean the rotor and stator components of the probe exposed to the air with clean water and a soft bristled brush;
After cleaning, wipe off any water stains;
If the calibration equipment carried is equipped with a battery, the negative terminal of the battery should be connected to the negative terminal of the DC power supply of the equipment. If the calibration equipment carried is not equipped with a battery, a wire should be directly led from the positive terminal of the DC power supply of the equipment to the stainless steel circular plate for calibration, and the stainless steel circular plate should be placed under the sensing surface of the probe (equidistant, close distance). The power supply voltage at this time should be recorded, and the theoretical electric field strength should be calculated using the electric field strength formula E=U/D. After that, the on-site coefficient calibration should be carried out. If the on-site environment is not open on the ground, in order to improve the accuracy of early warning, the equipment and software provided by the manufacturer should introduce environmental coefficient calibration as necessary.
Company contact information: 020-31195637 Fax: 020-31195729
Lightning Warning Division Straight Line: 18688405118
Website: www.ronglei.com.cn
Address: Building C2, Zone A, Jinying Industrial Zone, Changbian Village, Shiji Town, Panyu District, Guangzhou City, China Postal Code: 511450
