CN111327272A - Solar photovoltaic power supply monitoring system - Google Patents

Abstract

The application provides a solar photovoltaic power monitoring system, including a monitoring host, a programmable controller, a sensor component and a monitoring power module; the monitoring host has a touch screen; the programmable controller is connected with an expansion module through a parallel bus; the sensor component includes a photovoltaic voltage sensor , battery pack voltage sensor, load voltage sensor, temperature sensor, current sensor; the sensor component transmits the detected signal to the programmable controller or its expansion module; the monitoring host receives all the signals through the programmable controller and displays them in the on the touch screen. This application monitors the parameters such as voltage, current and temperature in the solar photovoltaic power generation system by monitoring the host and the programmable controller, and displays them on the touch screen, and can automatically and selectively turn on the generator power according to the power generation of the photovoltaic panels, Thereby ensuring the normal operation of the battery pack and the normal operation of the solar photovoltaic power generation system.

Description

A solar photovoltaic power monitoring system

technical field

The present application relates to the technical field of solar power generation monitoring, in particular to a solar photovoltaic power monitoring system.

Background technique

Photovoltaic power generation is based on the principle of photovoltaic effect, using solar cells to directly convert sunlight energy into electrical energy. Regardless of whether it is used independently or connected to the grid, the photovoltaic power generation system is mainly composed of three parts: solar panels (components), controllers and inverters. They are mainly composed of electronic components and do not involve mechanical parts. Therefore, photovoltaic power generation equipment Extremely refined, reliable and stable, long life, easy installation and maintenance.

Especially for remote areas, where there is no mains power (such as natural gas pipeline monitoring stations in remote areas), it is the preferred power supply scheme to combine generators and photovoltaic power generation systems as power sources; at present, this combined power supply scheme is due to lack of monitoring and control. It makes the fault difficult to be found and affects the normal operation of the above working scenarios.

SUMMARY OF THE INVENTION

The technical problem to be solved by this application is to provide a solar photovoltaic power monitoring system.

The technical problem further solved by the present application is to provide a solar photovoltaic power monitoring system for monitoring a solar photovoltaic power generation system; the solar photovoltaic power generation system includes a plurality of photovoltaic cell panels, a photovoltaic inverter corresponding to each photovoltaic cell panel, and A battery pack; the photovoltaic inverter is used for converting the power of the photovoltaic panel into direct current to charge the battery pack; the battery pack and/or the photovoltaic inverter are used for supplying power to the load through the load power module; it also includes power generation The generator power supply is used to charge the battery pack through the emergency charging module in emergency;

The monitoring system includes a monitoring host, a programmable controller signally connected to the monitoring host, a sensor assembly and a monitoring power supply module; the monitoring host has a touch screen and an alarm module; the programmable controller is connected through a parallel bus There is an expansion module; the monitoring power supply module is configured to supply power to the monitoring host, the sensor assembly, the programmable controller and the expansion module;

The sensor assembly includes a photovoltaic voltage sensor/photovoltaic current sensor for detecting the output voltage/current of the photovoltaic panel, a battery pack voltage sensor/battery pack current sensor for detecting the working voltage/current of the battery pack, and a load power module for detecting A load voltage sensor for outputting voltage, and a temperature sensor for detecting the ambient temperature of the battery; the sensor assembly transmits the detected voltage signal, temperature signal and current signal to the programmable controller or its expansion module;

The programmable controller is configured to:

Within the time range allowed to start the generator power supply, calculate the generated power of all photovoltaic panels according to the voltage signal of the photovoltaic voltage sensor and the current signal of the photovoltaic current sensor, and determine that the generated power is less than the set power generation When the voltage signal of the battery pack voltage sensor is less than the set voltage, the engine start signal is sent to the generator power supply;

Within the set time range that allows starting the generator power supply, when it is judged that the current signal of the battery pack current sensor is less than the set current, after a delay of the set time length, an oil engine stop signal is sent to the generator power supply;

Sending an oil engine stop signal to the generator power source outside the set time range that allows starting of the generator power source;

The monitoring host also receives, stores and displays the voltage signal, temperature signal and current signal through the programmable controller.

According to the technical solutions provided by the embodiments of the present application, the monitoring host has two background communication serial ports, which are respectively used to connect the local monitoring background and the remote monitoring background;

In the solar photovoltaic power generation system: the battery pack is provided with a battery pack switch and a battery pack fuse; the power generation system is provided with an insulation relay for detecting the insulation state of the DC bus;

The programmable controller is further configured to receive a battery switch status signal of the battery switch, a status signal of the battery fuse and a status signal of the insulation relay, and after receiving the battery switch Send an alarm signal to the monitoring host when the status signal is not closed or the status signal of the battery pack fuse is a fault signal or the status signal of the insulation relay is a fault signal;

The monitoring host is configured to: store the alarm signal after receiving the alarm signal, start the alarm module to alarm, and then send a comprehensive fault alarm signal to the local monitoring background.

According to the technical solutions provided by the embodiments of the present application, the photovoltaic inverter sends the status signal of the inverter to the monitoring host through a serial bus for storage and display.

According to the technical solutions provided by the embodiments of the present application, it further includes a battery inspection module, configured to detect the voltage signal of a single battery in the battery pack, convert the voltage signal into a digital signal, and transmit it to the battery through a serial RS485 bus. Programmable Controllers.

According to the technical solutions provided by the embodiments of the present application, the monitoring host is provided with a parameter setting module; the set voltage, set current, set power generation, set duration, and set the time range that allows starting the generator power Set by the parameter setting module;

The parameter setting module is configured to input the upper limit value of charging current, upper limit temperature value, overvoltage value, undervoltage value of the battery pack, the overvoltage value and undervoltage value of a single battery in the battery pack, and the touch screen The lighting duration and the alarm duration of the alarm module; the monitoring host determines whether to start the alarm module to alarm and monitor the background locally according to the voltage signal, temperature signal and current signal and various parameters set by the parameter setting module Send a comprehensive fault alarm signal;

The parameter setting module is further configured to input a working time period of the load power supply module; the monitoring host is configured to send a load power supply module startup command that meets the requirements of the working time period to the programmable control module; The load power module is made to work within the working time period.

According to the technical solutions provided by the embodiments of the present application, the monitoring host is a tablet computer.

According to the technical solutions provided by the embodiments of the present application, the programmable controller is a 6ES7-S7 module; the expansion module is an EM231 module.

According to the technical solution provided by the embodiment of the present application, it further includes a protection device for placing the tablet computer, the protection device includes a base with an open side, and a placement cavity for placing the tablet computer is formed in the middle of the base; The placement cavity is an inclined cavity with an opening higher than the bottom surface; a U-shaped mounting plate for clamping the tablet computer is placed in the placement cavity; the side of the mounting plate away from the tablet computer is provided with a protruding part extending from the bottom surface. the pull rod of the base;

The middle part of the placement cavity is slidably inserted with a primary sealing plate; the open top of the placement cavity is hinged with a secondary sealing plate; the outer end of the primary sealing plate is fixed with a pull rope, and the end of the pull rope The outer side of the secondary sealing plate is provided with an insertion hole for the pin to be inserted;

The external wiring of the tablet computer protrudes through the side of the base; the side of the base corresponds to the side button of the tablet computer and a plug is also inserted correspondingly.

According to the technical solutions provided in the embodiments of the present application, scrapers are provided on both sides of the primary sealing plate on the outside of the base; and a flexible layer is pasted on the outside of the scraper.

The advantages and positive effects of the present application are: because the present application adopts the above technical solution, that is, the output voltage of the photovoltaic panel, the output voltage of the inverter, the battery pack in the solar photovoltaic power generation system are monitored by the monitoring host and the programmable controller. The output voltage of the solar photovoltaic power generation system and the output voltage of the load power supply; the working environment temperature of the battery pack and other parameters are displayed on the touch screen, so that the working status of each module in the solar photovoltaic power generation system can be grasped in time, so as to detect faults in time and protect the solar energy. The monitoring system provided by the present application can selectively turn on the generator power according to the power generation of photovoltaic panels in a timely and automatic manner, so as to ensure the normal operation of the battery pack and the normal operation of the load equipment.

According to the technical solutions provided in the embodiments of the present application, by receiving the battery pack switch status signal of the battery pack switch, the status signal of the battery pack fuse and the status signal of the insulation relay in the photovoltaic power generation system, timely discovery The fault in the power generation system and the alarm signal are issued, which provides a guarantee for the normal operation of the photovoltaic power generation system.

According to the technical solutions provided in the embodiments of the present application, the monitoring host is further provided with a parameter setting module and an alarm module corresponding to each module in the solar photovoltaic power generation system, so that after monitoring the voltage signal, current signal and temperature signal of each module , can be compared with the set parameters, and start the alarm module in time according to the comparison result.

According to the technical solutions provided by the embodiments of the present application, a base is provided for the tablet computer, a placement cavity for preventing the tablet computer is arranged in the base, and a double sealing plate is set for the placement cavity; thus, the tablet computer can be protected in harsh environments. In the working environment, avoid excessive dust and gravel from entering the tablet computer and affect its work.

In addition to the technical problems solved by the present application, the technical features constituting the technical solutions, and the advantages brought by the technical features of the technical solutions described above, other technical problems that can be solved by a solar photovoltaic power monitoring system of the present application , other technical features included in the technical solution and the advantages brought by these technical features will be described in further detail in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is the principle block diagram of the solar photovoltaic power generation system in this application;

Fig. 2 is the principle block diagram of the solar photovoltaic power supply monitoring system in this application;

Fig. 3 is the circuit diagram of the solar photovoltaic power monitoring system in the application;

Fig. 4 is an enlarged view of part A in Fig. 3;

Fig. 5 is the enlarged view of B part among Fig. 3;

6 to 7 are schematic structural diagrams of the base in Embodiment 2. FIG.

In the picture: 10 solar photovoltaic power generation system; 11 photovoltaic panel; 12 photovoltaic inverter; 13 battery pack; 13-1. battery pack switch; 13-2 battery pack fuse; 14 load power module; 15 load; 16 power generation Machine power supply; 17 emergency charging module; 18 insulation relay; 21 monitoring host; 22 programmable controller; 26, remote monitoring background; 23 monitoring power module; 24 expansion module; 27 battery inspection module; 25 local monitoring background; 34 temperature Sensor; 35 Current Sensor; 36 Photovoltaic Current Sensor; 40 Protection Device; 41 Base; 42 Placement Cavity; 43 Mounting Plate; 48 jack; 49 scraper.

Detailed ways

The specific embodiments of the present application will be further described below with reference to the accompanying drawings. It should be noted here that the description of these embodiments is used to help the understanding of the present application, but does not constitute a limitation to the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no conflict with each other.

Example 1

This embodiment provides a solar photovoltaic power monitoring system for monitoring a solar photovoltaic power generation system; as shown in FIG. Inverter 12 and battery pack 13, wherein the battery pack 13 is composed of several single batteries; the photovoltaic inverter 12 is used to charge the battery pack 13 after converting the power of the photovoltaic panel 11 into direct current; the battery The group 13 and/or the photovoltaic inverter 12 are used to supply power to the load 15 through the load power supply module 14 ; in this embodiment, the solar photovoltaic power generation system 10 further includes charging the battery group 13 through the generator power supply 16 and the emergency charging module 17 . module for emergency use. The generator power source 16 may be a diesel generator or a gasoline generator.

In this embodiment, the load power supply module 14 is a voltage regulator module, which converts the DC power supply from the photovoltaic inverter 12 or the power supply of the battery pack 13 into a stable DC power supply, generally 24V or 48V, which is provided to the user. For communication equipment, in general, the load power module 14 converts the power supply of the battery pack 13 into a stable DC communication power supply. Because the voltage of the DC power supply output by the power supply of the battery pack 13 and the photovoltaic inverter 12 is unstable, a load power supply module 14 is required. Only after voltage conversion and voltage regulation can be supplied to the user's communication equipment, the communication equipment is generally a carrier wave machine, an optical transceiver, and an RPRS module for long-distance communication.

As shown in FIG. 2, the solar photovoltaic power monitoring system 20 provided in this embodiment includes a monitoring host 21, a programmable controller 22 signally connected to the monitoring host 21, a sensor component 30 and a monitoring power module 23; the monitoring host 21 is provided with a touch screen and an alarm module; the programmable controller 22 is connected with an expansion module 24 through a parallel bus;

The sensor assembly 30 includes a photovoltaic voltage sensor 31/photovoltaic current sensor 36 for detecting the output voltage/current of the photovoltaic panel 11, a battery pack voltage sensor 32 for detecting the working voltage of the battery pack 13, and a load power module 14 for detecting A load voltage sensor 33/battery pack current sensor 35 for outputting voltage/current, a temperature sensor 34 for detecting the ambient temperature of the battery; the sensor assembly 30 transmits the detected voltage signal, temperature signal and current signal to the programmable control controller 22 or its expansion module 24;

The programmable controller 22 is configured to:

Within the set time range that allows starting the generator power supply, the generated power of all photovoltaic panels is calculated according to the voltage signal of the photovoltaic voltage sensor 31 and the current signal of the photovoltaic current sensor 36, and it is judged that the generated power is less than the set power. When the power generation amount is fixed, and the voltage signal of the battery pack voltage sensor 32 is less than the set voltage, the engine start signal is sent to the generator power supply 16, and the battery pack 13 is charged in an emergency in a timely manner;

Within the time range allowed to start the generator power supply, when it is judged that the current signal of the battery pack current sensor 35 is less than the set current, the generator power supply 16 will be delayed for a set period of time and then send an oil engine stop signal;

Sending an oil engine stop signal to the generator power source 16 outside the time range allowed to start the generator power source;

Set the time range that allows to start the generator power, set power generation, set duration, set current, set voltage. These parameters are considered to be set in the monitoring host 10, and the monitoring host will then communicate with the programmable controller through the network port. Set to get. The data transmission between the monitoring host 10 and the programmable controller 22 can be realized through an Ethernet interface or through a serial interface.

The photovoltaic inverter 12 sends the inverter output status signal to the monitoring host 21 through the serial bus; therefore, the monitoring host 21 can also conveniently detect the monitoring operating parameters and fault status of the photovoltaic inverter 12; the status signal Including the output voltage, current, frequency, power, temperature and other signals of the photovoltaic inverter 12 .

The monitoring host 21 receives the voltage signal, the temperature signal and the current signal through the programmable controller 22 and processes and displays it on the touch screen; in this embodiment, the serial bus is an RS485 bus. In this monitoring system, the touch screen is a touch display screen, and the monitoring host 21 is provided with multiple display interfaces. For example, by receiving and storing the output voltage of each photovoltaic cell panel, the power generation and output of each photovoltaic cell panel in each time period can be calculated and obtained. Tabular data or curve data of voltage; for example, by receiving the output voltage of the battery pack 13 and the ambient temperature of the battery pack, the voltage and ambient temperature of the battery pack can be drawn into a curve or table that changes according to time, so as to facilitate viewing the entire solar energy The operating status of the photovoltaic system.

The monitoring power supply module 23 is configured to supply power to the monitoring host 21 , the programmable controller 22 , the sensor assembly 30 , and the expansion module 24 . In this embodiment, the output voltage of the monitoring power supply module 23 is a 24V DC power supply.

Wherein, the monitoring host has 2 background communication serial ports, which are respectively used to connect the local monitoring background 25 and the remote monitoring background 26; the monitoring host 10 can respectively set the communication parameters of these two communication serial ports;

In the solar photovoltaic power generation system: the battery pack 13 is provided with a battery pack switch 13-1 and a battery pack fuse 13-2; the solar photovoltaic power generation system is provided with an insulating relay 18 for detecting the insulation state of the DC bus ;

The programmable controller 22 is further configured to receive the battery pack switch status signal of the battery pack switch 13-1, the status signal of the battery pack fuse 13-2 and the status signal of the insulation relay 18, and Send an alarm signal to the monitoring host 10 when receiving that the switch status signal of the battery pack is not closed or the status signal of the battery pack fuse is a fault signal or the status signal of the insulation relay is a fault signal;

The programmable controller 22 is configured to: store the alarm signal after receiving the alarm signal, start the alarm module to alarm, and then send a comprehensive fault alarm signal to the local monitoring background 25 .

The alarm module is, for example, a buzzer; when any of the above-mentioned signals are generated, it indicates that the power generation system is faulty and needs to be repaired immediately.

The monitoring system further includes a battery inspection module 27, which is configured to detect the voltage signal of a single battery in the battery pack, convert the voltage signal into a digital signal, and transmit it to the programmable controller 22 through the serial RS485 bus. .

Wherein, in addition to sending a comprehensive fault alarm signal to the local monitoring background, the monitoring host 21 also communicates with the local monitoring background 25 and the remote monitoring background 26 through the following communication protocols:

Monitoring host The communication mode between the monitoring host 21 and the local monitoring background 25 and the remote monitoring background 26 can be any one of COM, RS232 and RS485, the baud rate is 9600, and the character format adopts no parity bit and 8 data bits. , Asynchronous serial communication format with 1 stop bit, master-slave communication structure, the default station number is 1/2, which can be set.

After the monitoring host sends a command, if no return data is received, wait for more than 500mS to send a new data packet. The monitoring host sends commands cyclically, and if no data is received for 5 consecutive cycles, a communication fault is set.

1. Take telemetry data (01H)

Order:

address function code STARTADDR Data length CRC check 01H 03H 0000H 000CH CRC16

return:

address function code length DATA CRC check 01H 03H 18H CRC16

Data Definition:

The arrangement order of floating-point double-word registers is high word first, low word last;

Remote message description:

In the above communication protocol, battery 01-battery 24 respectively refer to the 01st-24th battery in the battery pack; photovoltaic 1-photovoltaic 3 respectively refer to photovoltaic panel 1-photovoltaic panel 3;

In this embodiment, the programmable controller may be, for example, a 6ES7-S7 module or other programmable controllers; the expansion module may be, for example, an EM231 module.

According to the technical solutions provided by the embodiments of the present application, the monitoring host is provided with a parameter setting module; the set voltage, set current, set power generation, set duration, and set the time range that allows starting the generator power Set by the parameter setting module;

The parameter setting module is configured to input the upper limit value of charging current, upper limit temperature value, overvoltage value, undervoltage value of the battery pack, the overvoltage value and undervoltage value of a single battery in the battery pack, and the touch screen The lighting duration and the alarm duration of the alarm module; the monitoring host determines whether to start the alarm module to alarm and monitor the background locally according to the voltage signal, temperature signal and current signal and various parameters set by the parameter setting module Send a comprehensive fault alarm signal.

For example, when the signal of the battery pack voltage sensor 32 shows that the voltage exceeds the overvoltage value of the battery pack, the alarm module will issue an overvoltage alarm; when the signal of the battery pack voltage sensor 32 shows that the voltage is less than the undervoltage value of the battery pack, the alarm module will issue an overvoltage alarm. Undervoltage alarm; when the signal of the current sensor 35 shows that the current exceeds the upper limit value of the current of the battery pack, the alarm module will issue an upper limit current alarm; when the signal of the temperature sensor 34 shows that the current exceeds the upper limit value of the temperature of the battery pack, the alarm module will issue an alarm Temperature upper limit alarm; when any of the above alarm signals are generated, the monitoring host 10 will store and record the detailed information of the above alarm signals; at the same time, send a comprehensive fault alarm signal to the local monitoring background.

The buzzer will start according to the set alarm duration every time an alarm is generated. After the alarm duration expires, the buzzer will stop and start again until the next alarm signal is generated.

Example 2

On the basis of Embodiment 1, as shown in FIG. 3 , the monitoring system provided by this implementation further includes a protection device 40 for placing the tablet computer (ie, the monitoring host 21 ), and the protection device 40 includes a side The base 41 with an open side forms a placement cavity 42 for placing the tablet computer (that is, the monitoring host 21 ) in the middle of the base 41; the placement cavity 42 is an inclined cavity with an opening higher than the bottom surface; the placement cavity A U-shaped mounting plate 43 for clamping the tablet computer is placed; the side of the mounting plate 43 away from the tablet computer is provided with a pull rod 43-1 protruding from the base;

A primary sealing plate 44 is inserted into the middle of the placement cavity 42 slidably up and down; a secondary sealing plate 45 is hinged to the top of the opening of the placement cavity; A pin 47 is fixed at the end of the pull cord 46 ; an insertion hole 48 is provided on the outer side of the secondary sealing plate 45 for the pin 47 to be inserted into;

The external wiring of the tablet computer protrudes through the side of the base, and the external wiring such as power cord and data cable is optional, and these lines are provided with enough expansion and contraction in the placement cavity to avoid the situation of pulling the tablet computer when moving; The side of the base 41 corresponds to the side buttons of the tablet computer and also has insert blocks correspondingly inserted, and the control of the side buttons of the tablet computer can be realized by pressing the insert blocks.

Since the tablet computer is a sophisticated electronic device, it is easily damaged by dust and sand when it works outdoors for a long time. In this embodiment, by hiding the tablet computer in the base 41, as shown in FIG. 4, when the need When viewing and using, first pull out the primary sealing plate 44, and then push it to the opening of the placement cavity 42 through the pull rod 44, lift the secondary sealing plate 45 at this time, and insert the insertion hole through the pulling rope 46 and the pin 47 48 Fix the primary sealing plate 44 and the secondary sealing plate; then operate the tablet computer.

Preferably, the outside of the base 41 is provided with scrapers 49 on both sides of the primary sealing plate 44 ; the outer side of the scraper 49 is pasted with a flexible layer; the scraper 49 can be inserted into the primary sealing plate 44 Time to wipe off the dust on its surface.

The embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the described embodiments. For those of ordinary skill in the art, various changes, modifications, substitutions and alterations to these embodiments without departing from the principle and spirit of the present invention still fall within the protection scope of the present application.

Claims (9)

1. A solar photovoltaic power supply monitoring system is used for monitoring a solar photovoltaic power generation system; the solar photovoltaic power generation system comprises a plurality of photovoltaic cell panels, photovoltaic inverters corresponding to the photovoltaic cell panels and battery packs; the photovoltaic inverter is used for converting a power supply of a photovoltaic cell panel into direct current and then charging the battery pack; the battery pack and/or the photovoltaic inverter are used for supplying power to a load through the load power supply module; the emergency charging system further comprises a generator power supply, wherein the generator power supply is used for charging the battery pack through an emergency charging module in emergency;

the monitoring system is characterized by comprising a monitoring host, a programmable controller in signal connection with the monitoring host, a sensor assembly and a monitoring power module; the monitoring host is provided with a touch screen and an alarm module; the programmable controller is connected with an expansion module through a parallel bus; the monitoring power supply module is configured to supply power to the monitoring host, the sensor assembly, the programmable controller and the expansion module;

the sensor assembly comprises a photovoltaic voltage sensor/a photovoltaic current sensor for detecting the output voltage/current of the photovoltaic cell panel, a battery pack voltage sensor/a battery pack current sensor for detecting the working voltage/current of the battery pack, a load voltage sensor/a load current sensor for detecting the output voltage/current of the load power supply module, and a temperature sensor for detecting the ambient temperature of the battery; the sensor component transmits the voltage signal, the temperature signal and the current signal detected by the sensor component to a programmable controller or an expansion module thereof;

the programmable controller is configured to:

within a time range allowing a generator power supply to be started, calculating the power generation power of all photovoltaic cell panels according to the voltage signals of the photovoltaic voltage sensors and the current signals of the photovoltaic current sensors, judging that the power generation power is smaller than a set power generation amount, and sending an oil engine starting signal to the generator power supply when the voltage signals of the battery pack voltage sensors are smaller than a set voltage;

when the current signal of the battery pack current sensor is judged to be smaller than the set current within the time range allowing the generator power supply to be started, an oil engine stop signal is sent to the generator power supply after a set time is delayed;

sending an oil engine stop signal to a generator power supply outside a time range for setting permission of starting the generator power supply;

the monitoring host machine also receives, stores and displays the voltage signal, the temperature signal and the current signal through the programmable controller.

2. The solar photovoltaic power monitoring system of claim 1, wherein the monitoring host has 2 background communication serial ports for connecting a local monitoring background and a remote monitoring background, respectively;

in the solar photovoltaic power generation system: the battery pack is provided with a battery pack switch and a battery pack fuse; an insulation relay for detecting the insulation state of the direct current bus is arranged in the power generation system;

the programmable controller is also configured to receive a battery pack switch state signal of the battery pack switch, a state signal of the battery pack fuse and a state signal of the insulating relay, and send an alarm signal to the monitoring host when the battery pack switch state signal is not closed or the state signal of the battery pack fuse is a fault signal or the state signal of the insulating relay is a fault signal;

the monitoring host is configured to: and storing the alarm signal after receiving the alarm signal, starting the alarm module to alarm, and then sending a comprehensive fault alarm signal to the local monitoring background.

3. The solar photovoltaic power monitoring system of claim 2, wherein the photovoltaic inverter sends the inverter status signal to the monitoring host via a serial bus for storage and display.

4. The solar photovoltaic power monitoring system of claim 3, further comprising a battery polling module configured to detect voltage signals of individual batteries in the battery pack, convert the voltage signals into digital signals, and transmit the digital signals to the programmable controller through a serial RS485 bus.

5. The solar photovoltaic power supply monitoring system of claim 4, wherein the monitoring host is provided with a parameter setting module; the set voltage, the set current, the set power generation amount, the set duration and the set time range allowing the generator power supply to be started are set through the parameter setting module;

the parameter setting module is also configured to input a charging current upper limit value, a temperature upper limit value, an overvoltage value and an undervoltage value of the battery pack through the touch screen, the overvoltage value and the undervoltage value of a single battery in the battery pack, the lighting time of the touch screen and the alarm time of the alarm module; the monitoring host determines whether to start the alarm module to alarm or not according to the voltage signal, the temperature signal and the current signal and each parameter set by the parameter setting module and sends a comprehensive fault alarm signal to a local monitoring background;

the parameter setting module is also configured to input the working time period of the load power supply module; the monitoring host is configured to send a load power supply module starting command meeting the requirement of the working time period to the programmable control module; and enabling the load power supply module to work in the working time period.

6. The solar photovoltaic power monitoring system of claim 5, wherein the monitoring host is a tablet computer.

7. The solar photovoltaic power supply monitoring system of claim 6, wherein the programmable controller is a 6ES7-S7 module; the expansion module is an EM231 module.

8. The solar photovoltaic power supply monitoring system according to claim 7, further comprising a protection device for placing the tablet computer, wherein the protection device comprises a base with an open side, and a placing cavity for placing the tablet computer is formed in the middle of the base; the placing cavity is an inclined cavity with an opening higher than the bottom surface; a U-shaped mounting plate for clamping the tablet personal computer is placed in the placing cavity; a pull rod extending out of the base is arranged on one side, away from the tablet personal computer, of the mounting plate;

a primary sealing plate is inserted into the middle part of the placing cavity in a vertically sliding manner; a secondary sealing plate is hinged to the top end of the opening of the placing cavity; a pull rope is fixed at the outer end of the primary sealing plate, and a pin is fixed at the end part of the pull rope; the outer side of the secondary sealing plate is provided with a jack for inserting the pin;

the external wiring of the tablet personal computer extends out through the side edge of the base; the side of the base corresponds to the side key of the tablet computer and is correspondingly inserted with an insertion block.

9. The solar photovoltaic power supply monitoring system of claim 8, wherein scrapers are arranged on two sides of the primary sealing plate outside the base; and a flexible layer is adhered to the outer side of the scraper.

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