CN115313159A - Mobile intelligent safety power supply device and operation method - Google Patents

Abstract

A mobile intelligent safety power supply device and operation method, which include a device casing, a dry-type isolation transformer, a power equipment cabinet, a forklift port and a device side cover; a brand-new low-voltage grounding method is adopted, and the IT system is connected to a three-phase five-wire TN system. ‑S system is combined, the neutral point of the secondary side of the transformer is not grounded, the shell of the electrical equipment is grounded, and the working neutral line and the protection zero line are completely separated, the shell of the electrical equipment device is connected to the ground through the equipotential grounding line, and the power supply and the electrical equipment are connected to the ground. When the shell of the electrical equipment is connected, it will not cause harm to the human body, and the fault current is very low, which does not affect the normal operation of the equipment; the intelligent insulation monitoring system is used to monitor the insulation resistance and leakage capacitance of the line in real time, and reduce the insulation resistance of the low-voltage medium and large power grid to the ground capacitance. Detecting the influence of the system, improving the accuracy of fault diagnosis, and timely discovering circuit insulation faults, it can realize continuous power supply and effectively protect the personal safety of operators and equipment safety.

Description

Mobile intelligent safety power supply device and operation method

technical field

The invention belongs to the technical field of intelligent power supply, and relates to a mobile intelligent safe power supply device and an operation method.

Background technique

With the continuous expansion of the distribution network scale and the increase of distributed intermittent new energy power generation in the new power system, the complexity of the operating conditions of the distribution station area is increasing. Under overload pressure or other factors, faults such as short circuit and leakage of the line in the distribution station area are prone to occur, which directly affect the power quality and power supply safety of the station area.

In the process of low-voltage maintenance work, the regular preventive test of traditional power equipment and facilities has a certain effect on the detection of faults. check. Moreover, the test cycle required for regular preventive tests is long, and it cannot meet the production needs for lines that are in urgent need of electricity. Therefore, there is an urgent need for a device that can both supply power and monitor the insulation status of equipment. Safe and economical operation while improving the safety, stability, normal operation and control level of on-site power distribution line equipment.

At present, most insulation monitoring devices use current transformers to measure the output value of each circuit by injecting signals, calculate the resistance to ground, and judge the insulation status of the line. However, this method is greatly affected by the capacitance between the busbar and the ground, so there is an urgent need for a An insulation monitoring device that can reduce the influence of ground capacitance to improve the accuracy of insulation fault identification.

Contents of the invention

The technical problem to be solved by the present invention is to provide a mobile intelligent safety power supply device and its operation method, which adopts the low-voltage grounding method, and the housing of the electrical equipment device is connected to the earth through an equipotential grounding wire, and when the power supply is connected to the housing of the electrical equipment, It will not cause harm to the human body, and the fault current is very low, which does not affect the normal operation of the equipment; the intelligent insulation monitoring system is used to monitor the insulation resistance and leakage capacitance of the line in real time, reducing the impact of the low-voltage medium and large power grid's ground capacitance on the insulation detection system and improving Accurate fault diagnosis, timely detection of circuit insulation faults, continuous power supply and effective protection of personal safety and equipment safety of operators.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a mobile intelligent safety power supply device, which includes a device casing, a dry-type isolation transformer, a power equipment cabinet, a forklift port and a device side cover; the dry-type isolation The transformer is located in the housing, the power equipment cabinet is located on the side of the dry-type isolation transformer, the forklift port is located on the base of the lower part of the housing, and the device side cover is located on the side of the housing close to the dry-type isolation transformer; the power equipment cabinet includes sound and light alarms, voltage The circuit composed of selection button, reset button, control output circuit button, display screen, intelligent insulation monitoring system and output and input cable terminals.

The sound and light alarm is located on the top of the power equipment cabinet shell; the voltage selection button and reset button are located on the left side of the control output loop button; the voltage selection button, reset button, and control output loop button are located on the upper part of the power equipment cabinet; The lower part of the selection button, the reset button and the control output loop button, the intelligent insulation monitoring system is located at the lower part of the display screen; the output and input cable terminals are located at the lower part of the intelligent insulation monitoring system.

The sound and light alarm is used for alarming failure; the voltage selection button is used for selecting the output power supply voltage; the reset button is used for alarm reset and hardware reset; the control output circuit button is used for controlling the output circuit; the output and input cable terminals are used for plugging output and input cable.

It also includes grounding; the grounding type is a low-voltage grounding method, combining the IT system with the three-phase five-wire TN-S system, the neutral point of the secondary side of the transformer is not grounded, the shell of the electrical equipment is grounded, and the working zero line The neutral wires are completely separated.

The intelligent insulation monitoring system is composed of an intelligent controller, a signal generation module, an information collection module, a sensor module, an information transmission module, a decision-making module, a display module and an alarm module; the sensor module is composed of a current transformer, a voltage mutual inductor and a temperature sensor Composition; all modules are connected by an intelligent controller.

The display screen displays the output power supply voltage value, output current value, set insulation resistance value, actual insulation resistance value, leakage capacitance value, device temperature, set action insulation resistance and cut-off delay time; insulation resistance and leakage capacitance are related to the system Resistance and capacitance associated with impedance to ground; said set action includes alarm or cut-off.

The real-time online monitoring device of the intelligent insulation monitoring system outputs power supply voltage, output current, insulation resistance, leakage capacitance and operating temperature; when the leakage capacitance does not exceed the capacitance limit value, the safety threshold of the insulation resistance is judged in real time in combination with the load condition and an alarm and protection Output; when the leakage capacitance exceeds the capacitance limit, after replacing the current transformer with a higher precision, start the device again to monitor the insulation state of the line.

令

求解方程组，计算得线路绝缘电阻

和泄露电容值

其中Z为线路对地阻抗，

为线路电压，I_f为电流互感器检测泄漏电流，ω为电源频率，R为线路绝缘电阻值，C为泄露电容值，a和b为计算线路对低阻抗

所得复数的实部和虚部；当输出电流、装置温度、实际绝缘电阻值任何一个超过设定阈值时，显示屏上对应的值标红，同时装置进入报警状态，报警器启动；当装置处于报警状态，仍能工作；当泄露电容值超过限值电容后，装置进入超限状态，停止监测。The insulation resistance and leakage capacitance monitoring method is that the intelligent controller controls the signal injection module to inject a low-frequency AC signal into the monitored line, detects the leakage current I _f through a high-precision current transformer, and calculates the line-to-ground impedance

make

Solve the equations to calculate the line insulation resistance

and leakage capacitance values

Where Z is the line-to-ground impedance,

is the line voltage, I _f is the leakage current detected by the current transformer, ω is the power supply frequency, R is the line insulation resistance value, C is the leakage capacitance value, a and b are the calculated line pair low impedance

The real part and imaginary part of the obtained complex number; when any one of the output current, device temperature, and actual insulation resistance value exceeds the set threshold, the corresponding value on the display screen will be marked red, and the device will enter the alarm state at the same time, and the alarm will start; when the device is in In the alarm state, it can still work; when the leakage capacitance value exceeds the limit capacitance, the device enters the over-limit state and stops monitoring.

When the input voltage is three-phase 400V power frequency voltage and the output power supply voltage is three-phase five-wire 400V power frequency voltage, it will directly provide single-phase 220V power frequency voltage.

The operation method of the mobile intelligent safety power supply device as described above comprises the following steps:

S1. After the wiring is completed, turn the voltage selection button to the corresponding position, press the corresponding control output circuit button, and then close the switch. At this time, the display screen displays the output power supply voltage and output current;

S2, if the device enters the alarm state due to the output current, device temperature, and actual insulation resistance exceeding the threshold, find out the fault according to the red items displayed on the display screen and eliminate it as soon as possible;

S3, if the fault cannot be eliminated for a short time, you can first press the reset button to turn off the alarm. After the fault is eliminated, press and hold the reset button for three seconds. After the lock is released, turn on the power again;

S4, if the leakage capacitance of the device exceeds the capacitance limit value, the device enters the overrun state, and after replacing the current transformer with a higher precision, the device is switched on again to start the device.

The beneficial effects of the present invention are:

A new low-voltage grounding method is adopted to combine the three-phase five-wire TN-S system with the IT system. The neutral point of the secondary side of the transformer is not grounded, the shell of the electrical equipment is grounded, and the working zero line and the protection zero line are completely separated. , The grounding method has the advantages of both TN-S system and IT system, and overcomes the defects of the original TN-C system at the maintenance site.

The three-phase load is unbalanced, and the potential of the neutral point rises, but the shell has no potential, and the PE line also has no potential; when an insulation fault occurs, the current will not form a loop through the neutral point of the transformer; the shell of the electrical equipment is grounded, and when it touches the shell , the voltage will not cause harm to the human body, and the fault current is low.

Monitor the leakage capacitance of the system while monitoring the insulation resistance. When the leakage capacitance exceeds the capacitance limit, improve the accuracy of the current sensor, reduce the impact of the low-voltage medium and large power grid's ground capacitance on the insulation detection system, and improve the accuracy of fault diagnosis.

Output power supply voltage The beneficial effect of the present invention is: a new low-voltage grounding method is adopted, and the shell of the electrical equipment device is connected to the earth through the equipotential grounding wire. When touching the shell of the device, the voltage will not cause harm to the human body and the fault current is very low ≤1mA, reduce or avoid the risk of fire, while extending the life of the equipment.

The insulation monitoring system is used to monitor the insulation resistance and leakage capacitance of the line in real time, reduce the impact of the low-voltage medium and large power grid's ground capacitance on the insulation detection system, improve the accuracy of fault diagnosis, and timely detect circuit insulation faults. In terms of key power maintenance tasks and other tasks, continuous power supply can be achieved and the personal safety and equipment safety of operators can be effectively protected.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

Fig. 1 is the front view of the present invention.

Fig. 2 is the control block diagram of each module of the invention.

In the figure, 1-shell, 2-dry-type isolation transformer, 3-power equipment cabinet, 4-forklift port, 5-sound and light alarm, 6-voltage selection button, 7-reset button, 8-control output circuit button, 9-display screen, 10-intelligent insulation monitoring system, 11-output and input cable terminals, 12-device side cover.

Detailed ways

As shown in Figures 1 to 2, a mobile intelligent safety power supply device includes a device housing 1, a dry-type isolation transformer 2, a power equipment cabinet 3, a forklift port 4, and a device side cover 12; the dry-type isolation transformer 2 Located in the housing 1, the power equipment cabinet 3 is located on the side of the dry-type isolation transformer 2, the forklift port 4 is located on the base of the lower part of the housing 1, and the device side cover 12 is located on the side of the housing 1 close to the dry-type isolation transformer 2; the power equipment cabinet 3 includes a sound and light alarm 5, a voltage selection button 6, a reset button 7, a control output circuit button 8, a display screen 9, an intelligent insulation monitoring system 10, and a circuit composed of output and input cable terminals 11.

Preferably, the size of the housing 1 is 1700mm×900mm×1400mm, which is convenient to move.

In a preferred solution, the sound and light alarm 5 is located on the top of the power equipment cabinet 3 shell; the voltage selection button 6 and the reset button 7 are located on the left side of the control output circuit button 8; the voltage selection button 6, the reset button 7, the control output circuit The button 8 is located on the upper part of the power equipment cabinet 3; the display screen 9 is located at the lower part of the voltage selection button 6, the reset button 7 and the control output circuit button 8, and the intelligent insulation monitoring system 10 is located at the lower part of the display screen 9; the output and input cable terminals 11 It is located at the lower part of the intelligent insulation monitoring system 10 .

In a preferred solution, the sound and light alarm 5 is used to alarm failure; the voltage selection button 6 is used to select the output power supply voltage; the reset button 7 is used for alarm reset and hardware reset; the control output loop button 8 is used to control the output loop; Output and input cable terminals 11 are used for plugging output and input cables.

In the preferred solution, grounding is also included; the grounding type is a low-voltage grounding method, the IT system is combined with the three-phase five-wire TN-S system, the neutral point of the secondary side of the transformer is not grounded, and the shell of the electrical equipment is grounded, and The working zero line is completely separated from the protection zero line.

In a preferred solution, the intelligent insulation monitoring system 10 is composed of an intelligent controller, a signal generation module, an information collection module, a sensor module, an information transmission module, a decision-making module, a display module and an alarm module; the sensor module is composed of a current transformer, a voltage Composed of mutual inductors and temperature sensors; all modules are connected by an intelligent controller.

Preferably, the intelligent controller adopts MSP430F5438 single-chip microcomputer to control each module.

Preferably, the signal generation module uses AN77100-15 low-voltage AC source to inject signals into the monitored line.

Preferably, the information acquisition module uses an ADS8364 chip to perform A/D sampling on the sensor signal, and calculate the insulation resistance R and leakage capacitance C at the same time.

Preferably, the information transmission module uses the ZigBee wireless communication protocol to transmit data, and finally transmits the data to the decision-making module through the 65LBC184 chip.

Preferably, the sensor module adopts ZLB-C61 zero flux current sensor, HV-C54-xxxP5O9 voltage sensor and DS18B20 temperature sensor.

Preferably, the decision-making module uses a 74LS85 binary comparator to compare the relationship between the insulation resistance R, the leakage capacitance C and the temperature and the set threshold, and output the compared signal to the display module and the alarm module.

Preferably, the display module controls the OLED8080 display screen through the STM32103ZET6 microcontroller.

Preferably, the alarm module adopts an active buzzer.

In a preferred solution, the display screen 8 displays the output power supply voltage value, output current value, set insulation resistance value, actual insulation resistance value, leakage capacitance value, device temperature, set action insulation resistance and cut-off delay time; insulation resistance and leakage capacitance are the resistance and capacitance associated with the impedance of the system to ground; the setting action includes alarm or cut-off.

In a preferred solution, the intelligent insulation monitoring system 10 real-time online monitoring device outputs power supply voltage, output current, insulation resistance, leakage capacitance and operating temperature; when the leakage capacitance does not exceed the capacitance limit, the insulation resistance is judged in real time in combination with the load condition Safety threshold and alarm and protection output; when the leakage capacitance exceeds the capacitance limit, after replacing the current transformer with a higher precision, start the device again to monitor the line insulation status.

Preferably, the current sensor is a high-precision current transformer, and the device is equipped with three kinds of precision current transformers, which are 0.1s level, 0.2s level, and 0.5 level; the order of accuracy is 0.1s level > 0.2s level > 0.5 level.

令

求解方程组，计算得线路绝缘电阻

和泄露电容值

其中Z为线路对地阻抗，

为线路电压，I_f为电流互感器检测泄漏电流，ω为电源频率，R为线路绝缘电阻值，C为泄露电容值，a和b为计算线路对低阻抗

所得复数的实部和虚部；当输出电流、装置温度、实际绝缘电阻值任何一个超过设定阈值时，显示屏上对应的值标红，同时装置进入报警状态，报警器启动；当装置处于报警状态，仍能工作；当泄露电容值超过限值电容后，装置进入超限状态，停止监测。In a preferred solution, the insulation resistance and leakage capacitance monitoring method is to inject a low-frequency AC signal into the monitored line through the intelligent controller control signal injection module, detect the leakage current I _f through a high-precision current transformer, and calculate the line-to-ground impedance

make

Solve the equations to calculate the line insulation resistance

and leakage capacitance values

Where Z is the line-to-ground impedance,

is the line voltage, I _f is the leakage current detected by the current transformer, ω is the power supply frequency, R is the line insulation resistance value, C is the leakage capacitance value, a and b are the calculated line pair low impedance

The real part and imaginary part of the obtained complex number; when any one of the output current, device temperature, and actual insulation resistance value exceeds the set threshold, the corresponding value on the display screen will be marked red, and the device will enter the alarm state at the same time, and the alarm will start; when the device is in In the alarm state, it can still work; when the leakage capacitance value exceeds the limit capacitance, the device enters the over-limit state and stops monitoring.

In a preferred solution, when the input voltage is a three-phase 400V power frequency voltage and the output power supply voltage is a three-phase five-wire 400V power frequency voltage, a single-phase 220V power frequency voltage is directly provided.

In a preferred solution, the operation method of the above-mentioned mobile intelligent safety power supply device includes the following steps:

S1. After the wiring is completed, turn the voltage selection button to the corresponding position, press the corresponding control output circuit button, and then close the switch. At this time, the display screen displays the output power supply voltage and output current;

S2, if the device enters the alarm state due to the output current, device temperature, and actual insulation resistance exceeding the threshold, find out the fault according to the red items displayed on the display screen and eliminate it as soon as possible;

S3, if the fault cannot be eliminated for a short time, you can first press the reset button to turn off the alarm. After the fault is eliminated, press and hold the reset button for three seconds. After the lock is released, turn on the power again;

S4, if the leakage capacitance of the device exceeds the capacitance limit value, the device enters the overrun state, and after replacing the current transformer with a higher precision, the device is switched on again to start the device.

In the preferred scheme,

When the input side is energized, the output power supply voltage loop is closed manually or automatically, and the loop can be cut off manually or automatically.

In order to prevent incorrect output power supply voltage caused by misoperation, the output power supply voltage and current value are displayed on the display.

The mobile intelligent safety power supply device has display function, intelligent detection function, protection function and reset function.

Display function:

The display screen displays output power supply voltage value V, output current value A, set insulation resistance value kΩ, actual insulation resistance value kΩ, leakage capacitance value μF, device temperature °C, set action insulation resistance kΩ, and cut-off delay time s.

Intelligent detection function:

a. Data collection:

Collect output power supply voltage V, output current A, device temperature °C, actual insulation resistance value kΩ, leakage capacitance value μF.

b. Insulation fault action

Protective function:

Device protection items include output current, device temperature, actual insulation resistance value, and leakage capacitance value.

When any one of the output current, device temperature, and actual insulation resistance value exceeds the set threshold, the corresponding value on the display screen will be marked red, and the device will enter the alarm state at the same time, and the alarm will start. When the device is in an alarm state, it can still work. When the leakage capacitance value exceeds the limit capacitance, the device enters the overrun state and stops monitoring.

When the device is in the alarm state, if the value of the protection item returns to the normal range within the cut-off delay time, the device will exit the alarm state.

When the device is in the alarm state, if the reset button is pressed, the alarm will be turned off; after stopping, if the value of the protection item still does not meet the normal conditions, the device will still be in the alarm state.

When the device is in the alarm state, if the duration reaches the set time, the device will alarm again.

When the device is in the alarm state and the power is cut off, the power is turned on again, and the device is still in the alarm state. The device can only be reset by pressing the reset button.

When the alarm time reaches the set value or the value of the protection item exceeds the protection threshold, that is, the protection threshold > the alarm threshold, the device immediately cuts off the power and enters the protection state.

When the device is in the protected state, the device can only be reset by pressing the reset button.

Alarm and protection conditions:

a. Output current > alarm threshold, the device enters the alarm state and starts the countdown of the cut-off delay time; output current > protection threshold, the device cuts off the power immediately and enters the protection state.

b. When the temperature > temperature alarm threshold, the device enters the alarm state. When in the alarm state, the temperature of the device becomes a normal value, and the alarm is released. If the time in the alarm state exceeds the cut-off delay time, the device will automatically cut off the power supply.

c. The actual insulation resistance value < cut-off threshold value, the device immediately cuts off the power supply and enters the protection state; the cut-off threshold value < actual insulation resistance value < cut-off threshold value × 4, the device enters the alarm state but does not cut off the power supply; the device is in the alarm state, when the actual insulation resistance When the value meets > cut-off threshold × 4, the alarm will be cleared.

d. Leakage capacitance value>capacitance limit value, the device enters the overrun state, then the current intelligent monitoring system cannot monitor the insulation state of the system, and a current transformer with a higher precision should be replaced.

System parameters:

Output current alarm threshold: I _a *1.1A, I _a is the rated output current;

Output current protection threshold: I _a *1.25A, I _a is the rated output current;

Device temperature alarm threshold: transformer internal temperature alarm threshold 110°C temperature rise alarm threshold 75°C;

Set action insulation resistance kΩ: 250kΩ;

Capacitance limit: 40μF for small grid, 500μF for medium grid, 2000μF for large grid;

Overcurrent cut-off delay time: 30s;

Overtemperature cut-off delay time: 1h;

Set the operating insulation resistance and cut-off delay time to be adjustable manually.

Reset function:

There are two types of reset: alarm reset and hardware reset.

a. Alarm reset: Short press the reset button to turn off the alarm in the alarm state; long press the reset button for 3 seconds to reset the device in the alarm state and unlock it.

b. Hardware reset: Press and hold the reset button for more than 3s. Used to reset the device when the system crashes.

The above-mentioned embodiments are only preferred technical solutions of the present invention, and should not be regarded as limitations on the present invention. The embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other if there is no conflict. The scope of protection of the present invention shall be the technical solution described in the claims, including equivalent replacements for the technical features in the technical solution described in the claims. That is, equivalent replacement and improvement within this range are also within the protection scope of the present invention.

Claims (10)

1. The utility model provides a portable intelligent security power supply unit, characterized by: the device comprises a device shell (1), a dry-type isolation transformer (2), a power equipment cabinet (3), a forklift port (4) and a device side cover (12); the dry type isolation transformer (2) is positioned in the shell (1), the power equipment cabinet (3) is positioned on one side of the dry type isolation transformer (2), the forklift port (4) is positioned on a base at the lower part of the shell (1), and the device side cover (12) is positioned on one side of the shell (1) and is close to the dry type isolation transformer (2); the power equipment cabinet (3) comprises an audible and visual alarm (5), a voltage selection button (6), a reset button (7), a control output loop button (8), a display screen (9), an intelligent insulation monitoring system (10) and a loop formed by an output cable terminal and an input cable terminal (11).

2. The mobile intelligent safety power supply device according to claim 1, wherein: the audible and visual alarm (5) is positioned at the top end of the shell of the power equipment cabinet (3); the voltage selection button (6) and the reset button (7) are positioned on the left side of the control output loop button (8); the voltage selection button (6), the reset button (7) and the control output loop button (8) are positioned at the upper part of the power equipment cabinet (3); the display screen (9) is positioned at the lower parts of the voltage selection button (6), the reset button (7) and the control output loop button (8), and the intelligent insulation monitoring system (10) is positioned at the lower part of the display screen (9); the output and input cable terminals (11) are located at the lower part of the intelligent insulation monitoring system (10).

3. The mobile intelligent safety power supply device of claim 1, wherein: the audible and visual alarm (5) is used for alarming faults; the voltage selection button (6) is used for selecting and outputting the power supply voltage; the reset button (7) is used for alarm reset and hardware reset; the control output loop button (8) is used for controlling an output loop; the output and input cable terminals (11) are used for connecting output and input cables.

4. The mobile intelligent safety power supply device according to claim 1, wherein: the device also comprises a grounding device; the grounding mode is a low-voltage grounding mode, an IT system is combined with a three-phase five-wire system TN-S system, a neutral point of a secondary side of a transformer is not grounded, a shell of electric equipment is grounded, and a working zero line and a protection zero line are completely separated.

5. The mobile intelligent safety power supply device according to claim 1, wherein: the intelligent insulation monitoring system (10) consists of an intelligent controller, a signal generating module, an information acquisition module, a sensor module, an information transmission module, a decision-making module, a display module and an alarm module; the sensor module consists of a current transformer, a voltage mutual inductor and a temperature sensor; all modules are connected by an intelligent controller.

6. The mobile intelligent safety power supply device of claim 1, wherein: the display screen (8) displays an output power supply voltage value, an output current value, a set insulation resistance value, an actual insulation resistance value, a leakage capacitance value, a device temperature, a set action insulation resistance and a cut-off delay time; insulation resistance and leakage capacitance are resistance and capacitance associated with system impedance to ground; the setting action comprises alarming or cutting off.

7. The mobile intelligent safety power supply device according to claim 1, wherein: the intelligent insulation monitoring system (10) monitors the output power voltage, the output current, the insulation resistance, the leakage capacitance and the working temperature of the device on line in real time; when the leakage capacitance does not exceed the capacitance limit value, the safety threshold value of the insulation resistance is judged in real time by combining the load condition, and alarm and protection output are carried out; when the leakage capacitance exceeds the capacitance limit value, the device is started again to monitor the insulation state of the line after the current transformer with higher precision is replaced.

8. The mobile intelligent safety power supply device according to claim 6, wherein: the method for monitoring the insulation resistance and the leakage capacitance comprises the steps that a signal injection module is controlled by an intelligent controller to inject low-frequency alternating current signals into a monitored line, and leakage current I is detected through a high-precision current transformer _f And via calculating line impedance to ground

Order to

Solving equation set, calculating to obtain insulation resistance of circuit

And leakage capacitance value

Where Z is the line-to-ground impedance,

is line voltage, I _f For current transformer detection of leakage current, ω is power frequency, R is line insulation resistance value, C is leakage capacitance value, a and b are calculated line pair low impedance

Real and imaginary parts of the resulting complex numbers; when any one of output current, device temperature and actual insulation resistance valueWhen the number of the alarm exceeds the set threshold value, the corresponding value on the display screen is marked with red, and meanwhile, the device enters an alarm state and the alarm is started; when the device is in an alarm state, the device can still work; and when the leakage capacitance value exceeds the limit value capacitance, the device enters an overrun state and stops monitoring.

9. The mobile intelligent safety power supply device of claim 8, wherein: when the input voltage is three-phase 400V power frequency voltage and the output power voltage is three-phase five-line 400V power frequency voltage, single-phase 220V power frequency voltage is directly provided.

10. The operation method of the mobile intelligent safety power supply apparatus according to any one of claims 1 to 9, comprising the steps of:

s1, after wiring is finished, rotating a voltage selection button to a corresponding position, pressing a corresponding control output loop button, then switching on, and displaying output power supply voltage and output current on a display screen at the moment;

s2, if the device enters an alarm state because the output current, the temperature of the device and the actual insulation resistance value exceed a threshold value, finding out a fault according to a red marking item displayed by a display screen and removing the fault as soon as possible;

s3, if the fault cannot be eliminated in a short time, firstly pressing a reset button, turning off the alarm, pressing the reset button for three seconds after the fault is eliminated, and switching on again after the locking is released;

and S4, if the leakage capacitance value of the device exceeds the capacitance limit value, the device enters an overrun state, and the device is switched on again after the current transformer with higher precision is replaced.

Images