CN204575735U - A kind of ground current monitoring device and outdoor current monitoring system - Google Patents

Abstract

The utility model provides a grounding current monitoring device and an outdoor current monitoring system. The device includes a current transformer module, a data acquisition and overcurrent protection module, a data processing and communication module; the current transformer module is used for monitoring current value, and send the current value to the data acquisition and over-current protection module; the data acquisition and over-current protection module converts the current value into a digital signal and sends it to the data processing and communication module. Displayed on the display screen, and according to the value of the digital signal, the overcurrent protection resistor with corresponding resistance value is connected, or the overcurrent protection resistor is not connected; the data processing and communication module is used to display the current value and transmit current value and alarm information. The device and system of the utility model can realize on-line monitoring of the ground wire current, display and early warning according to the monitored current, and perform over-current protection by connecting over-current protection resistors with different resistance values.

Description

A grounding current monitoring device and an outdoor current monitoring system

technical field

The utility model relates to the technical field of current detection, in particular to a grounding current monitoring device and an outdoor current detection system.

Background technique

The power transformer is one of the key equipment in the power system. It is often regarded as the "heart" of the power grid. Its normal operation is an important guarantee for the safe, reliable, stable and economical operation of the power system. When the power transformer is in normal operation, the iron core must be reliably grounded at one point, and only one point is grounded. Since there will be a floating position between the iron core and the earth, there will be a ground current, which is very small under normal circumstances. After the transformer iron core is grounded at multiple points, a loop will be formed between the iron core and the earth. At this time, the grounding current will increase many times, which will endanger the normal operation of the transformer. Short-circuit overheating will cause partial burning of the iron core or damage to the windings in severe cases, resulting in inter-turn or phase-to-phase faults; secondly, due to the circulation of the grounding wire of the iron core, local overheating of the transformer will occur, resulting in discharge faults.

In power transformers of large-scale high-voltage electrical equipment, due to core ground faults and other abnormal conditions, various gases will be generated in the insulating oil. The usual detection method in the power sector is to detect the faulty gas dissolved in the insulating oil, and to conduct gas chromatographic analysis after sampling the insulating oil of the equipment, and to measure the current of the grounding lead wire of the external grounding bushing of the transformer core with a clamp ammeter. In order to find latent faults as soon as possible, it is the main means to ensure the safe operation and normal maintenance of large power transformers. However, when detecting the multi-point grounding phenomenon of the iron core, it is difficult to distinguish the weak ground fault current from the strong electromagnetic environment interference. This method has many steps, complicated operation, and cannot be analyzed online. There is a problem. And it is manually measured by the operator with a clamp-type ammeter every day or every week, which not only wastes a lot of manpower and material resources, but also forces some unattended stations with low voltage levels to measure less than once a week, which is for the safety of electrical equipment in substations. The operation left hidden dangers.

Utility model content

(1) Technical problems to be solved

The technical problem to be solved by the utility model is how to capture the instantaneous change of the ground wire current online, and give an early warning to the captured instantaneous current.

(2) Technical solutions

In order to solve the above technical problems, the utility model provides a ground current monitoring device, the device includes a current transformer module, data acquisition and overcurrent protection module, data processing and communication module;

The current transformer module includes a current transformer for monitoring the current value and sending the current value to the data acquisition and overcurrent protection module;

The data acquisition and overcurrent protection module includes an analog-to-digital converter, a display screen, and an overcurrent protection resistor; the analog-to-digital converter converts the current value into a digital signal and sends it to the data processing and communication module. display on the above-mentioned display screen, and according to the digital signal, the over-current protection resistor is not connected, or the over-current protection resistor with corresponding resistance value is connected;

The data processing and communication module includes a display screen and a parameter setting button, the display screen is used to display the current value and the alarm current value, and the parameter setting button is used to set the alarm current value.

Preferably, the data processing and communication module uploads the current value to the computer through the field bus, or uploads the current value to the mobile phone through wireless communication, and sets and modifies the mobile phone number through the parameter setting button.

Preferably, the data processing and communication module transfers and stores data to an external storage device through a USB interface.

Preferably, the overcurrent protection of the data acquisition and overcurrent protection module is provided with three levels of current limiting protection, and an overcurrent protection resistor with a different resistance value is set corresponding to each level of the current limiting protection.

Preferably, the data collection and overcurrent protection module communicates with the data processing and communication module through RS485 communication, and the data processing and communication module is connected to nine data collection and overcurrent protection modules at the same time.

Preferably, the accuracy of the current transformer is 0.1mA, and it has a filter circuit.

Preferably, the data acquisition and overcurrent protection module is installed vertically or on a wall, and is integrated with the current transformer and installed at the incoming ground terminal; the data processing and communication module is installed on a wall.

Preferably, the data acquisition and overcurrent protection module, current transformer module, data processing and communication module are all integral structures or detachable structures.

Preferably, the current measurement range of the device is 1mA-100A, the accuracy within 1-100mA is ±1mA, and the accuracy within 100mA-100A is ±1%.

An outdoor current monitoring system, characterized in that the system includes the above-mentioned grounding current monitoring device.

(3) Beneficial effects

The utility model provides a grounding current monitoring device and an outdoor current monitoring system. The device and the system of the utility model can realize on-line monitoring of the grounding wire current, and perform display and early warning according to the monitored current. The overcurrent protection resistor is used for overcurrent protection. In addition, the device and system of the present invention support long-distance transmission, and can transfer and store data into external storage devices, which enhances the reliability of the system; the measurement range of the device and system of the present invention It is 1mA～100A, the accuracy is ±1mA within 1～100mA, and the accuracy within 100mA～100A is ±1%. The device system will not be damaged within 10-100A.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic structural diagram of a ground current monitoring device of a preferred embodiment of the present invention;

Fig. 2 is a signal processing flowchart of a ground current monitoring device of a preferred embodiment of the present invention;

Fig. 3 is a diagram of an initialization interface diagram of a data processing and communication module of a ground current monitoring device according to a preferred embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail. The following examples are used to illustrate the utility model, but cannot be used to limit the scope of the utility model.

Fig. 1 is a schematic structural diagram of a ground current monitoring device according to a preferred embodiment of the present invention; the ground current monitoring device includes a current transformer module, data acquisition and overcurrent protection module 2, data processing and communication Module 3; the current transformer module includes a current transformer 1 for monitoring the current value, and the current value is sent to the data acquisition and overcurrent protection module 2; the data acquisition and overcurrent protection module 2 It includes an analog-to-digital converter, a display screen, and an overcurrent protection resistor; the analog-to-digital converter converts the current value into a digital signal and transmits it to the data processing and communication module for display on the display screen, and according to The value of the digital signal connects the overcurrent protection resistor of the corresponding resistance value, or does not connect the overcurrent protection resistor; the data processing and communication module 3 includes a display screen and a parameter setting button, and the display screen is used for The current value and the alarm current value are displayed, and the parameter setting button is used to set the alarm current value.

The device can realize on-line monitoring of the ground wire current, display and early warning according to the monitored current, and perform over-current protection by connecting over-current protection resistors with different resistance values.

The data processing and communication module 3 uploads the current value to the computer through the field bus, or uploads the current value to the mobile phone through wireless communication, and sets and modifies the mobile phone number through the parameter setting button. The data processing and communication module transfers and stores data into an external storage device through a USB interface. The overcurrent protection of the data acquisition and overcurrent protection module is provided with three levels of current limiting protection, and corresponding to each level of the current limiting protection, overcurrent protection resistors with different resistance values are set. The data acquisition and overcurrent protection module communicates with the data processing and communication module through RS485 communication, and the data processing and communication module is connected to nine data acquisition and overcurrent protection modules at the same time. The accuracy of the current transformer is 1 mA, and it has a filter circuit. The data acquisition and overcurrent protection module is installed vertically or on the wall, and is integrated with the current transformer and installed on the grounding terminal; the data processing and communication module is installed on the wall and integrates a dehumidification device. The data acquisition and overcurrent protection module, the current transformer module, the data processing and communication module are all integral structures or detachable structures. The current measurement range of the device is 1mA-100A, the accuracy within 1-100mA is ±1mA, and the accuracy within 100mA-100A is ±1%. The system is not damaged within 10-100A.

The device of the utility model performs overcurrent protection by connecting overcurrent protection resistors with different resistance values, and can transfer and store data into an external storage device, thereby enhancing the reliability of the system.

The current transformer module in the device of the present utility model includes a current transformer, which is used for real-time high-precision and reliable current collection, and detects changes in the transformer core ground current and clip ground current, and the detected data is provided to the data collection and overcurrent protection module. The current transformer is a through-core installation with a size of 100×10×60. It can accurately measure the ground current in a strong electromagnetic environment and output current signals at the same time, which can effectively reduce external electromagnetic interference and ensure that the data is not polluted. The accuracy can reach 0.1mA, and it is waterproof, moisture-proof and anti-interference.

The data acquisition and overcurrent protection module performs analog-to-digital conversion on the current value obtained from the current transformer module, displays the current value on the display screen, conducts comprehensive analysis, and judges whether to input the overcurrent protection resistor and the resistance of the overcurrent protection resistor. value, and upload the digital signal of the current value to the data processing and communication module. The data acquisition and overcurrent protection module is vertically or wall-mounted, integrated with the current transformer in the same box, and installed near the iron core and the grounding lead of the clip. The data acquisition and over-current protection module adopts RS485 bus interface with super lightning protection measures, which is convenient for networking and has waterproof, moisture-proof and anti-interference functions. The installation size (mm) of the non-resistor network is: 300*350*180, and the installation storage of the resistor network is 550*650*180.

The data acquisition and overcurrent protection module is equipped with three levels of current limiting protection: I, II, and III. Each level of current limiting will automatically compensate a resistance with a certain resistance value, and at the same time automatically record the compensation switching process, and perform local and remote monitoring. After the alarm and current limiting protection timing is up, the compensation system can be automatically detected; when the detected fault disappears, the compensation system will automatically exit and the iron core will be directly grounded.

The data processing and communication module is used to display the grounding current of the iron core and the clip in real time and upload alarm information in time. The real-time current value of the LCD color screen, including real-time value and alarm value, can be set and modified by the parameter setting button to set and modify the upper and lower limits of the alarm value, and modify the mobile phone number; it is also connected to the computer through the field bus to realize remote monitoring and query data information; data processing And the communication module can connect up to 9 sets of data acquisition and overcurrent protection modules, which is convenient for centralized control. When the current in a certain place exceeds the set alarm threshold, the data processing and communication module will alarm with the sound and the current value displayed in different colors, and at the same time send the alarm information and fault location information to the mobile phone of the operation and maintenance personnel through the GPRS module. So that troubleshooting can quickly determine the location. The data processing and communication module has its own dehumidification device, which is widely used in areas with large temperature and humidity changes, and adopts stainless steel spray plastic, which is rainproof, dustproof, anti-corrosion, anti-ultraviolet radiation, and can work outdoors for a long time; wall-mounted installation, The size is 400*410*120.

The data processing and communication module can automatically turn the screen to display the current of multiple sets of transformer cores and clips; it can be set to automatic current limiting mode and unlimited current mode, that is, it can independently decide whether to connect to the overcurrent protection resistor and to connect to the overcurrent The resistance value of the protection resistor has strong autonomy; the modbus or 61850 protocol communication protocol can be selected for data transmission with external devices;

The data processing and communication module can conveniently dump real-time current data through an external storage device, which is convenient for staff to perform data analysis and fault handling. The data processing and communication module can set the date, time and current alarm threshold value through the parameter setting button, and the current threshold data can be restored to the factory value through the parameter setting button, and the over-current alarm data within one year can be queried. Setting a password when setting parameters and exporting data can effectively protect corporate privacy.

When the current exceeds the limit somewhere, the data processing and communication module will sound an alarm, and at the same time, the abnormal data area will turn white, and the alarm information and fault location information will be sent to the mobile phone of the operation and maintenance personnel through the GPRS module. This device can assist professionals to quickly judge whether there is multi-point grounding in the transformer core by capturing instantaneous current changes, so as to prevent problems before they happen. The current limiting device in Figure 1 can be a current limiting resistor, or any component that can play a role in current limiting.

The liquid crystal display of the data processing and communication module can automatically turn over the screen to display multiple sets of transformer cores, clip currents, and alarm information.

On the other hand, the utility model is also combined with oil chromatographic analysis to perform online maintenance, evaluation, early warning and risk analysis on the status of electrical equipment.

The working process of the ground current monitoring device of the embodiment of the utility model is shown in Figure 2, including the following steps:

1. Current detection process: The current signal is collected by the current transformer fixed on the iron core and the clamp grounding wire, and the signal is filtered to output a stable current signal with little interference.

2. Current signal analog-to-digital conversion process: the data acquisition and overcurrent protection module receives the current signal, analyzes and processes the signal and outputs a digital signal, displays the current value on the spot through the LCD screen, and transmits it to the data processing through the transmission cable and communication modules.

3. Online display process of current signals in various places: the data processing and communication module analyzes and processes the digital signals transmitted from various places, and displays them on the LCD screen immediately.

4. Alarm process: When the current value somewhere is too large, the CPU will judge whether it exceeds the alarm threshold value. If it exceeds the door alarm threshold value, the CPU will send commands to the relay and the display screen, and the relay responds quickly and sends a signal to the speaker. Power on makes an alarm sound, and the current value on the LCD screen turns red, and at the same time, the CPU will send an instruction to the GPRS module, and the module will send a short message to the mobile phone of the operation and maintenance personnel after receiving the instruction; if the current If the value does not exceed the alarm threshold value, the CPU will not issue an instruction.

5. Alarm elimination process: When the current value drops, the CPU will judge whether the current value exceeds the alarm threshold value. If it is lower than the alarm threshold value, the CPU will send a stop command to the relay, and the alarm sound will stop at this time. The CPU will send corresponding instructions to the LCD screen, and the red display of the LCD screen will also return to normal display; if the current value is still higher than the alarm threshold value, the CPU will not issue instructions, and the alarm will continue. ” key to turn off the alarm sound, but the current value is still displayed in white.

A grounding current monitoring device of the present invention can set various parameters of the system through the operation panel of the data processing and communication module, as shown in Figure 3, and can also complete the real-time control of various functions of the system through the operation panel , the operation process is as follows:

1. Parameter setting: Press the "Enter" key to enter the system menu, and use the "Up" and "Down" keys to select functions. When the cursor stays at the "Parameter Setting", press the "Enter" key and enter the password to enter the system parameter setting submenu middle.

① Time and date setting: In the pop-up setting menu, use the "up" and "down" keys to "select time setting", press "confirm" and then use the "up" and "down" keys to select the size, and press the "left" "Right" key to select the item, after the completion, the cursor moves to the end, press "OK" to complete the time setting.

②Mobile phone number setting: In the pop-up setting menu, select "Mobile phone number setting" through the "Up" and "Down" keys, press "OK" and then use the "Up" and "Down" keys to select the size, and press the "Left" """Right" key to select the item, after the completion, the cursor moves to the end, press "OK" to complete the setting of the mobile phone number.

③Alarm threshold current setting: In the pop-up setting menu, select "Current Protection Parameters" through the "Up" and "Down" keys, press "OK" and then use the "Up" and "Down" keys to select the size, and press "Confirm" is to complete the alarm current threshold setting.

④Password setting: In the pop-up setting menu, select "Password Setting" through the "Up" and "Down" keys, press "OK" and then use the "Up" and "Down" keys to select the size, and press the "Left" and "Right" keys to select the password setting. key to select the item, press "OK" after completion to complete the password setting

⑤Parameter restoration: In the pop-up setting menu, press the "up" and "down" keys to select "parameter restoration", and press "confirm" to restore the alarm current threshold to the factory value.

⑥If you need to exit a certain item setting, you can press the "ESC" key to return to the previous submenu. If you need to exit the setting, you can press the "ESC" key several times until you exit the setting menu.

2. Functional operation

① Alarm mute: When the device emits an alarm sound due to an overcurrent fault somewhere, press the "Mute" button, and the system alarm sound will stop.

②Save data into the memory card: insert the memory card into the data processing and communication module and press the "OK" button to enter the system menu, press the "Up" and "Down" buttons to select the function, and press the "OK" button when the cursor stays at the "Data Export" " key and then input the password to save the historical data and alarm current data into the memory card.

③Alarm event query: Press the "Enter" key to enter the system menu, use the "Up" and "Down" keys to select functions, press "Enter" when the cursor stays at the "Alarm Event Query" to enter the alarm data menu, and check the alarm time, Position, level, current value.

The utility model also discloses an outdoor current monitoring system, which includes the above-mentioned grounding current monitoring device.

In summary, a grounding current monitoring device and an outdoor current monitoring system provided by the utility model have the following advantages:

1. Structural features: The data acquisition and overcurrent protection module adopts an iron shell to ensure effective shielding of external electromagnetic interference. The iron shell is sprayed with insulating paint, which can effectively prevent the iron shell from rusting and ensure the insulation of the iron shell. The shell is well sealed and has the characteristics of moisture-proof and dust-proof. The data processing and communication module adopts an iron shell with a curved structure, which is beautiful and generous, and can effectively shield external electromagnetic interference. The shell is trapezoidal after being laid flat, which is convenient for the staff to sit or stand to watch; the keys of the data processing and communication module are mainly round. Shaped structure, simple and beautiful, convenient for staff to operate; the 7-inch LCD screen can display 9 sets of current data in real time, and can monitor more transformer equipment than other products; the use of high-precision current transformers can accurately measure grounding in strong electromagnetic environments Current, while outputting current signals can effectively reduce external electromagnetic interference and ensure that data is not polluted.

2. Functional features: real-time current can be displayed in the data acquisition and overcurrent protection module and the data processing and communication module, and the change of current can be displayed in the form of a graph in the data processing and communication module, which is convenient for the staff to understand the history Changes and predict the trend of current changes; when an over-current situation occurs, the system can not only alarm through the sound and the current value displayed in red, but also send the alarm information (including alarm time, location, and current value information) to the staff. On the mobile phone, so that the staff can find the over-current fault in time; press the "Mute" button to stop the alarm sound, but the current value is still displayed in red before the current returns to normal, so as to remind the staff in real time that there is an over-current fault; within 60 days The historical current data and alarm data are transmitted to the external storage device, which is convenient for the staff to collect data and make daily reports.

3. Operating characteristics: low power consumption during normal operation, low noise, wide temperature range, strong anti-interference ability, and stable operation in harsh environments; data acquisition and overcurrent protection modules can transmit current transformers The analog signal is converted into a digital signal, and then remotely transmitted to the data processing and communication module through the 485 communication cable, which can effectively solve the problem of analog signal transmission distortion caused by external electromagnetic interference, and is easy to install, easy to maintain, and reliable in operation; data The acquisition and overcurrent protection module and the data processing and communication module can display the measured current value synchronously in real time, which is convenient for the staff in the field and office to observe the change of the current in real time; it can be directly set in the data processing and communication terminal according to the needs of different users Current alarm threshold value, at the same time, the alarm current threshold value can also be restored to the factory value, and the user can set it according to the actual situation of the transformer site.

4. Maintenance features: The data acquisition and overcurrent protection module and the data processing and communication module all use highly integrated chips and components, which is convenient for maintenance personnel to quickly determine the fault location.

In addition, it should be noted that the utility model can realize online monitoring of various ground currents.

The above embodiments are only used to illustrate the utility model, but not to limit the utility model. Although the present utility model has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications or equivalent replacements of the technical solutions of the present utility model will not depart from the spirit and scope of the technical solutions of the present utility model. All should be included in the scope of claims of the present utility model.

Claims (10)

1. A ground current monitoring device, characterized in that the device comprises a current transformer module, data acquisition and overcurrent protection module, data processing and communication module; The current transformer module includes a current transformer for monitoring the current value and sending the current value to the data acquisition and overcurrent protection module; The data acquisition and overcurrent protection module includes an analog-to-digital converter, a display screen, and an overcurrent protection resistor; the analog-to-digital converter converts the current value into a digital signal and sends it to the data processing and communication module. display on the above-mentioned display screen, and according to the digital signal, the over-current protection resistor is not connected, or the over-current protection resistor with corresponding resistance value is connected; The data processing and communication module includes a display screen and a parameter setting button, the display screen is used to display the current value and the alarm current value, and the parameter setting button is used to set the alarm current value. 2. The device according to claim 1, wherein the data processing and communication module uploads the current value to the computer through the field bus, or uploads the current value to the mobile phone through wireless communication, and through the The parameter setting button sets and modifies the mobile phone number. 3. The device according to claim 2, wherein the data processing and communication module transfers and stores data into an external storage device through a USB interface. 4. The device according to claim 1, characterized in that, the overcurrent protection of the data acquisition and overcurrent protection module is provided with three levels of current limiting protection, and the current limiting protection of each level is set with different resistance values. current protection resistor. 5. The device according to claim 4, wherein the data acquisition and overcurrent protection module communicates with the data processing and communication module through RS485 communication, and the data processing and communication module are connected to multiple a data acquisition and overcurrent protection module. 6. The device according to claim 1, characterized in that the accuracy of the current transformer is 0.1 mA and has a filter circuit. 7. The device according to claim 1, characterized in that, the data acquisition and overcurrent protection module is vertical or wall-mounted, and is integrated with the current transformer and installed at the incoming ground terminal; the data processing And the communication module is wall-mounted. 8 . The device according to claim 7 , wherein the data collection and overcurrent protection module, current transformer module, data processing and communication module are all integral structures or detachable structures. 9. The device according to any one of claims 1 to 8, characterized in that the current measurement range of the device is 1 mA to 100 A, the accuracy within 1 to 100 mA is ±1 mA, and the accuracy within 100 mA to 100 A is ±1 %. 10. An outdoor current monitoring system, characterized in that the system comprises the device according to claims 1-9.