CN206930736U - One kind is used for high-tension cable many reference amounts detection means - Google Patents

Abstract

A multi-parameter detection device for high-voltage cables, relating to a detection device. At present, the commonly used method is to detect the temperature change of the high-voltage cable joint part or the change of the partial discharge signal to judge whether there is an insulation problem in the cable, and the accuracy is low. The utility model comprises a cable bus current acquisition module, a signal acquisition module and a signal conditioning module; the cable bus current acquisition module is used to obtain working electric energy from the cable bus and detect the cables, which includes a high-voltage cable current transformer, Offset impact signal unit, intelligent charging and discharging conditioning unit and matching output unit. The technical solution can collect the temperature of the cable joint, the load of the cable busbar, the circulation of the cable grounding and the partial discharge signal of the cable in real time and synchronously, reducing the misjudgment rate.

Description

A multi-parameter detection device for high-voltage cables

technical field

The utility model relates to a detection device, in particular to a multi-parameter detection device for high-voltage cables.

Background technique

Power cables are widely used in modern power system networks due to their good electrical, thermal and mechanical properties. With the continuous improvement of the system voltage level, high-voltage cables have become a very important part of the cable network. With the continuous completion of ultra-high voltage and ultra-high voltage projects in the power grid, high-voltage cables will surely become the main component of the future cable transmission network. Compared with traditional overhead lines, cables do not take up space on the ground, mostly underground or underwater, and do not require supporting facilities such as poles and towers; they receive much less external interference than overhead lines; and the dielectric loss is small. However, after long-term operation, due to aging and deterioration of the insulation, moisture, overheating or mechanical damage, the insulation of the cable will deteriorate. Common faults are mainly enhanced by multi-point grounding, overheating of joint temperature and partial discharge. If it is mild, it will affect the normal and stable transmission of electric energy and increase the loss of electric energy transmission. Seriously, it will cause blackout accidents, causing huge economic losses, and affecting the normal electricity consumption of enterprises and residents.

At present, the common method to ensure the safe operation of cables is to detect the insulation level of high-voltage cables, mainly based on preventive tests. This method has relatively large limitations and cannot detect the insulation degradation caused by long-term operation of cables. In response to this problem, domestic scholars have proposed a method of using a device to detect changes in the electrical quantity of high-voltage cables to judge cable insulation degradation. The commonly used means are to use the temperature device to detect the temperature change of the high-voltage cable joint part to judge the cable insulation deterioration, or use the high-frequency device to detect the change of the partial discharge signal of the high-voltage cable to judge whether there is an insulation problem in the cable. This method of judging the degree of cable insulation deterioration through the collection of a single electrical quantity by the device has certain effects, but it also has obvious disadvantages: sudden changes in the external temperature or interference from electromagnetic signals will affect the normal operation of the device, making the staff vulnerable to high voltage The insulation level of the cable produces misjudgment, which in turn affects the safe and stable operation of the power system.

Utility model content

The technical problem to be solved and the technical task proposed by the utility model are to perfect and improve the existing technical solutions, and to provide a multi-parameter detection device for high-voltage cables, so as to reduce costs and facilitate collection. For this reason, the utility model takes the following technical solutions.

Cable bus current power acquisition module, signal acquisition module and signal conditioning module; the cable bus current power acquisition module is used to obtain working power from the cable bus and detect the cables, which includes a high-voltage cable current transformer and a counteracting impact signal unit , an intelligent charging and discharging conditioning unit and a matching output unit; the signal acquisition module is used for synchronously collecting cable joint temperature signals, cable bus load, grounding non-flow and cable partial discharge signals, which includes a cable joint temperature detection unit, a cable bus A current detection unit, a cable metal outer sheath grounding circulation detection unit and a cable partial discharge detection unit; the signal conditioning module is used for signal conditioning and protection, which includes a signal processing unit and a signal protection unit.

This technical solution adopts the cable bus current power acquisition module to obtain working electric energy without external power supply, which avoids the detection failure caused by independent power supply failure; the unique signal acquisition module of the device can simultaneously detect the temperature of high-voltage cable joints, high-voltage cable grounding circulation, cable Four parameters of amplifier signal and cable bus load. By detecting the changes in the electrical parameters of four high-voltage cables to judge the deterioration of the cable insulation, the detection accuracy is greatly improved, the probability of misjudgment by the staff is reduced, and it is of great significance to ensure the safe and stable operation of high-voltage cables.

As a further improvement and supplement to the above technical solution, the utility model also includes the following additional technical features.

Further, the high-voltage cable current transformer, the offsetting impact signal unit, the intelligent charging and discharging conditioning unit, and the matching output unit are connected in sequence; the high-voltage cable current transformer obtains electric energy through sensing the cable load to supply power for the entire device; the offsetting impact signal unit Limit, stabilize, rectify, and filter the induced current, and transmit the current to the intelligent charging and discharging conditioning unit; the intelligent charging and discharging conditioning unit adjusts the input voltage and current to match the energy sensed by the high-voltage cable current transformer in real time , in order to achieve the purpose of maintaining the output power as the maximum power; the matching output unit provides DC energy through the whole set of matching circuits.

Further, the temperature detection unit of the cable joint includes a fiber grating device, the fiber grating device is close to the surface of the cable joint, and is wound and fixed with a high-voltage insulating heat shrinkable tape, and the winding thickness is 5 mm; the fiber grating device includes a light source , a circulator and a fiber grating temperature sensor, the light source generates a light source, and the temperature signal collected by the fiber grating sensor is collected through the circulator.

Further, the cable bus current detection unit cable is used to detect the transmission load of the high-voltage cable, which includes an integral Rogowski coil, a large current limiting circuit and an impact protection circuit. The cable bus current detection unit is a split structure, which includes a cable bus The right piece of the current detection unit and the left piece of the cable bus current detection unit, the right piece of the cable bus current detection unit and the left piece of the cable bus current detection unit are plugged to form a circular through hole, the right piece of the cable bus current detection unit and the cable bus current detection unit The splicing surface of the left piece is provided with a magnet to realize suction. The circular opening and closing magnetic suction structure with slots can be directly placed on the cable without affecting the normal operation of the cable, ensuring the easy operability of the device.

Further, the cable partial discharge detection unit is used to detect the high-frequency partial discharge signal of the high-voltage cable, and its acquisition frequency range is 30KHz to 26MHz; the cable partial discharge detection unit includes a square high-frequency current transformer, and the high-frequency current transformer is set on the cable It induces current and induces voltage in the secondary circuit; the high-frequency current transformer is equipped with a shielded shell, which is an open-close structure, which includes the left piece of the cable partial discharge detection unit and the right piece of the cable partial discharge detection unit, and the cable partial discharge detection unit. The left piece of the discharge detection unit and the right piece of the cable partial discharge detection unit are plugged together to form a square through hole, and the splicing surface of the left piece of the cable partial discharge detection unit and the right piece of the cable partial discharge detection unit is provided with a magnet to achieve attraction.

Further, the signal processing unit includes a cable joint temperature signal processing module, a cable bus current signal processing module, a cable metal outer sheath grounding circulation signal processing module, and a cable high-frequency partial discharge signal processing module; the cable joint temperature signal processing module includes a miniature spectrometer , which outputs the received temperature signal of the temperature detection unit of the cable joint through the A output port; the cable bus current signal processing module uses the limiter circuit, the filter circuit, the protection circuit and the impedance matching circuit to the cable bus collected by the bus current detection unit. The load signal is processed, and then through the signal protection unit, it is transmitted from the B output port to the data acquisition card; the cable ground circulation signal processing module processes the cable ground circulation signal collected by the ground circulation detection unit through the amplification circuit, filter circuit and detection circuit, After passing through the signal protection unit, it is transmitted to the data acquisition card from the C output port; the cable high-frequency partial discharge signal processing module processes the high-frequency partial discharge signal collected by the partial discharge detection unit through the limiting circuit, filter circuit and detection circuit. The circuit protection module and impedance matching circuit, and then through the signal protection unit, are transmitted from the D output port to the data acquisition card; the cable joint temperature signal processing module, the cable bus current signal processing module, the cable metal outer sheath grounding circulation signal processing module and the cable The high-frequency partial discharge signal processing module is protected by an independent shielding box.

Beneficial effect:

1) Using the cable bus current acquisition module to obtain working power, the cable can be detected without an external power supply, avoiding the detection failure caused by the failure of the external power supply;

2) The signal acquisition module can collect the temperature of the cable joint, the load of the cable busbar, the circulation of the cable grounding and the partial discharge signal of the cable in real time and synchronously. The temperature change at the cable joint can be detected in real time through the temperature detection unit of the cable joint; the bus load can be detected in real time through the cable bus current detection unit; the ground circulation current of the cable metal outer sheath can be detected in real time by the ground circulation detection unit of the cable metal sheath, and then the cable grounding can be judged Fault; through the cable partial discharge detection unit, the high-frequency partial discharge signal of the cable can be detected in real time. The powerful function of collecting multiple parameters in real time greatly enhances the utilization rate of equipment, improves the detection efficiency, and steadily improves the detection accuracy. High voltage cable detection and maintenance pressure.

3) The signal conditioning module is used to integrate the cable joint temperature signal processing module, the cable bus current signal processing module, the cable grounding circulation signal processing module and the cable high-frequency partial discharge signal processing module

Piece. It is protected by a special shielding box, which has strong anti-interference ability and waterproof and anti-fouling ability.

Description of drawings

Figure 1 is a structural diagram of a device for multi-parameter detection of high-voltage cables;

Figure 2 is a schematic diagram of the cable bus current taking module;

Fig. 3 is a working principle diagram of the temperature detection unit of the cable joint;

Fig. 4 is a working principle diagram of the temperature detection unit of the cable joint;

Fig. 5 is a cable partial discharge detection unit model;

Figure 6 is a schematic diagram of the working principle of the signal processing unit.

In the figure: 1 is the high-voltage cable busbar; 2 is the ground wire; 3 is the grounding circulation detection unit of the cable metal outer sheath; 4 is the cable partial discharge detection unit; 5 is the cable bus current detection unit; 6 is the temperature detection unit of the cable joint ; 7 is a cable connector; 8 is the signal input channel T of the signal conditioning module; 9 is the signal input channel Z of the signal conditioning module; 10 is the signal input channel Y of the signal conditioning module; 11 is the signal input channel X of the signal conditioning module; 12 is the signal output channel D of the signal conditioning module; 13 is the signal output channel C of the signal conditioning module; 14 is the signal output channel B of the signal conditioning module; 15 is the light source generation acquisition device; 16 is the signal conditioning module; 17 is the signal conditioning The first output channel of the signal of the module; 18 is the data acquisition card; 19 is the power-taking module of the cable bus current; 20 is the signal line interface of the cable bus current detection unit; 21 is the right piece of the cable bus current detection unit; 22 is the cable bus current detection Unit fixed slot; 23 is the left piece of the cable bus current detection unit; 24 is the fixed slot of the cable partial discharge detection unit; 25 is the signal line interface of the cable partial discharge detection unit; 26 is the left piece of the cable partial discharge detection unit; 27 is the cable Partial discharge detection unit right piece.

detailed description

The technical solution of the utility model is described in further detail below in conjunction with the accompanying drawings of the description.

As shown in FIG. 1 , the utility model is mainly composed of three parts: a cable bus current fetching module 19 , a signal acquisition module and a signal conditioning module 16 . Compared with the existing high-voltage cable detection device, the utility model adopts the cable bus current power acquisition module 19 to obtain working electric energy, and the cable can be detected without external power supply. The cable bus current power-taking module 19 mainly includes: high-voltage cable current transformer, counteracting impact signal unit, Supercapacitor intelligent charging and discharging conditioning unit, matching output unit, etc., with the help of the cable metal sheath circulation local energy-taking device, which simplifies the equipment , to avoid detection failure caused by external power failure. The signal acquisition module is composed of four parts: cable joint 7 temperature detection unit 6 , cable bus current detection unit 5 , cable metal outer sheath grounding circulation detection unit 3 and cable partial discharge detection unit 4 . The temperature detection unit 6 of the cable joint 7 can detect the temperature change at the cable joint 7 in real time; the cable bus current detection unit 5 can detect the load of the high-voltage cable bus 1 in real time; the cable metal outer sheath ground circulation detection unit 3 can detect the cable ground circulation in real time, Then judge the cable grounding fault; The four detection units work independently without interference with each other, and can collect multiple parameters synchronously in real time. The temperature detection unit 6 of the cable joint 7 collects the temperature of the cable joint 7 by means of a fiber grating device, which is input to the signal conditioning module 16 through the X channel 11 by means of the light source generation collection device 15; the bus current detection unit 5 uses a coil made of zinc ferrite to detect and collect The cable bus load is input to the signal conditioning module 16 through the Y channel 10; the ground circulation detection unit 3 detects and collects the cable ground circulation, and is input to the signal conditioning module 16 through the Z channel 9; the partial discharge detection unit 4 adopts a Rogowski coil, which has excellent The anti-interference ability can be used to detect and collect 3kHz-28MHz ultra-broadband cable partial discharge signals, which are input to the signal conditioning module 16 through the T channel. The three detection units collect three-way signals, input the signal conditioning module 16 through X, Y, Z, T channels 11, 10, 9, and 8, pass through a series of amplification, filtering, and detection circuits of the signal processing unit, and then pass through the signal protection unit , and finally input to the signal acquisition card.

A device for multi-parameter detection of high-voltage cables, including

1: Cable bus current take-off module 19

The cable bus current taking module 19 (as shown in FIG. 2 ) mainly includes: a high-voltage cable current transformer, a counter-shock signal unit, a Supercapacitor intelligent charging and discharging conditioning unit, and a matching output unit. The high-voltage cable current transformer obtains electric energy by sensing the cable load to supply power for the whole set of equipment; the offsetting impact signal unit limits, stabilizes, rectifies, and filters the induced current, and transmits the current into the Supercapacitor intelligent charging and discharging conditioning unit; Supercapacitor intelligent charging The discharge conditioning unit adjusts the voltage and current charged into the Supercapacitor to match it with the energy sensed by the high-voltage cable current transformer in real time, so as to maintain the maximum output power; the matching output unit provides DC energy through the matching circuit set.

The main technical parameters of the cable bus current taking module 19 are:

Two: Design of signal acquisition module (real-time synchronous acquisition of temperature signal of cable joint 7, cable busbar load, cable grounding circulation, cable partial discharge signal)

The signal processing module includes a cable joint 7 temperature detection unit 6 , a cable bus current detection unit 5 , a cable metal outer sheath grounding circulation detection unit 3 and a cable partial discharge detection unit 4 . The design principles of the four signal processing modules are as follows:

(1) Cable connector 7 temperature detection unit 6

The temperature detection unit 6 of the cable joint 7 is used to detect the temperature change of the cable joint 7. In order to ensure that the temperature signal of the joint can be collected quickly and accurately, a new type of fiber grating device is used. Due to the complex working environment of the cable, the ambient temperature is easy to change, and it is easy to As a result, the measured temperature of the device is lower than the actual temperature of the cable joint 7, so an optimized device installation method is adopted to attach the fiber grating device to the surface of the cable joint 7, and wrap and fix it with a high-voltage insulating heat shrinkable tape with a thickness of 5mm. The light source is generated by means of the light source generating and collecting device 15, and the temperature signal collected by the fiber grating device is collected through the circulator.

The working principle of the temperature detection unit 6 of the cable joint 7 is shown in Figure 3:

(2) Cable bus current detection unit 5

The cable bus current detection unit 5 is used to detect the transmission load of the high-voltage cable, and the design algorithm is improved to optimize the outer integral Rogowski coil, and the built-in large current limiting circuit and the impact protection circuit. The external integral Rogowski coil can be used to achieve the frequency selection effect, and the frequency is fixed at 50Hz by detecting the current of the busbar 1 of the high-voltage cable. Through actual testing, the 50Hz power frequency current flowing through the cable can be accurately collected. The shape of the cable bus current detection unit 5 adopts a circular open-close magnet adsorption design with a slot, which can be directly placed on the cable without affecting the normal operation of the cable, ensuring the easy operability of the equipment. The magnet adsorption design cooperates with the slot to fix, so that the cable bus current detection unit 5 can run stably.

The main technical parameters of the cable bus current detection unit 5 are:

The model of the cable bus current detection unit 5 is shown in Figure 4, which includes the right piece 21 of the cable bus current detection unit and the left piece 23 of the cable bus current detection unit; The signal line interface 20 of the cable bus current detection unit on the sheet 23; the right sheet 21 of the cable bus current detection unit and the left sheet 23 of the cable bus current detection unit are connected through the fixed slot 22 of the cable bus current detection unit.

(3) Cable metal outer sheath grounding circulation detection unit 3

The cable metal outer sheath grounding circulation detection unit 3 is used to detect the high-voltage cable grounding circulation, and the grounding fault can be judged according to the magnitude of the current. The shape adopts a circular opening and closing magnet adsorption design with a slot, which can be directly placed on the cable under test. It is convenient to take and place without affecting the normal operation of the cable. 50Hz to achieve the effect of detecting the grounding circulation of the metal outer sheath of the cable. The material is Permalloy. With the limiter circuit, filter circuit, and the amplification circuit, the effect of accurately detecting the grounding circulation can be achieved.

The main technical parameters of the cable metal outer sheath grounding circulation detection unit 3 are:

(4) Design of cable partial discharge detection unit 4

The cable partial discharge detection unit 4 is used to detect the high-frequency partial discharge signal of the high-voltage cable. The core component of the detection unit is a square high-frequency current transformer, which is not affected by magnetic saturation. Its working principle is to induce current through the cable and induce voltage in the secondary circuit. The partial discharge signal of the cable is characterized by steep wave front, short duration and wide frequency band. In view of this feature, the high-frequency loss low-nickel-zinc ferrite is used to make the coil. The signal acquisition frequency range of the cable partial discharge detection unit 4 is 30KHz-26MHz. The shape is a magnetic adsorption type that can be opened and closed.

a. Magnetic core material selection

According to the characteristics of the power cable partial discharge signal having a wide frequency spectrum and small amplitude, the ferrite material is selected to make the magnetic core. The ferrite materials commonly used to make magnetic cores mainly include manganese zinc ferrite, nickel zinc ferrite and so on. The magnetic permeability of different materials is applicable to different frequencies.

If the detection frequency is higher than the applicable range of the material itself, the magnetic permeability of the material will drop very seriously as the frequency of the detection signal increases. The lower initial permeability and higher cut-off frequency of NiZn 200 ferrite are more suitable for detecting the signal frequency of cable partial discharge.

b. Selection of coil turns

The number of turns of the coil directly affects the operating frequency band and sensitivity of the cable partial discharge detection unit 4, by the transfer function:

After simplification, we can get:

It can be seen from the formula that the sensitivity of the square high-frequency current transformer is inversely proportional to the number of coil turns and proportional to the self-integrating resistance in the applicable frequency band. In order to ensure the sensitivity and frequency range of the cable partial discharge detection unit 4, the upper limit frequency calculation formula and the lower limit frequency calculation formula are used to calculate, and through multiple sets of test tests, the number of coil turns is finally selected as 12 turns, and the self-integrating resistance is 1.2kΩ. Under this parameter, the cable partial discharge detection unit 4 has a good frequency bandwidth and high sensitivity.

c. Shielded shell design

In order to shield the interference of many external electromagnetic wave noise signals in the working environment of the partial discharge detection unit 4 of the cable, a shielding shell is designed for the square high-frequency current transformer. The shielding case is a square opening and closing magnet adsorption type with a slot. The material is aluminum with built-in magnets.

The main technical parameters of cable partial discharge detection unit 4 are:

The model of cable partial discharge detection unit 4 is shown in Figure 5: cable partial discharge detection unit 4 includes cable partial discharge detection unit left piece 26, cable partial discharge detection unit right piece 27, cable partial discharge detection unit left piece 26 or cable partial discharge The right piece 27 of the detection unit is provided with the signal line interface 25 of the cable partial discharge detection unit;

Three: Signal conditioning module 16

The signal conditioning module 16 is mainly composed of a signal processing unit and a signal protection unit.

The signal processing unit includes a cable joint 7 temperature signal processing module, a cable bus current signal processing module, a cable metal outer sheath grounding circulation signal processing module and a cable high-frequency partial discharge signal processing module. The temperature signal processing module of the cable joint 7 is mainly composed of a miniature spectrometer, which is small in size and ensures the accuracy and sensitivity of the cable temperature detection. The received temperature signal of the temperature detection unit 6 of the cable joint 7 is output from the A output port 17; The bus current signal processing module processes the cable bus load signal collected by the bus current detection unit 5 through the limiting circuit, filter circuit, protection circuit and impedance matching circuit, and then passes through the signal protection unit, and then transmits it to the data acquisition card through the B output port 14 18. The cable ground circulation signal processing module processes the cable ground circulation signal collected by the ground circulation detection unit 3 through the amplification circuit, the filter circuit and the detection circuit, and then passes through the signal protection unit, and is transmitted to the data acquisition card 18 by the C output port 13; The high-frequency partial discharge signal processing module of the cable processes the high-frequency partial discharge signal collected by the partial discharge detection unit 4 through the limiting circuit, the filter circuit and the detection circuit, with the help of the circuit protection module and the impedance matching circuit, and then through the signal protection unit. The D output port 12 transmits to the data acquisition card 18. The four modules of the signal processing unit are respectively protected by four special shielding boxes, which have strong anti-interference ability and waterproof and anti-fouling ability.

The signal protection unit mainly includes an overcurrent protection circuit, an overvoltage protection circuit and an impedance matching circuit. When the signals output by the cable bus current signal processing module, the cable metal outer sheath grounding circulation signal processing module and the cable high-frequency partial discharge signal processing module exceed the data acquisition card 18 acquisition capacity, it can limit the signal and protect the acquisition card. .

The working principle diagram of the signal conditioning module 16 is shown in FIG. 6 .

The multi-parameter detection device for high-voltage cables shown in the above figure is a specific embodiment of the utility model, which has already reflected the substantive features and progress of the utility model, and can be used according to actual needs under the inspiration of the utility model , equivalent modification of its shape, structure, etc., are all within the scope of protection of this scheme.

Claims (6)

1. A multi-parameter detection device for high-voltage cables, characterized in that it comprises: a cable bus current take-off module, a signal acquisition module and a signal conditioning module; the cable bus current take-off module is used to obtain working power to the cable bus And the cable is detected, which includes a high-voltage cable current transformer, an offsetting impact signal unit, an intelligent charging and discharging conditioning unit, and a matching output unit; Current and cable partial discharge signals, which include the temperature detection unit of the cable joint, the cable bus current detection unit, the cable metal outer sheath grounding loop current detection unit and the cable partial discharge detection unit; the signal conditioning module is used for signal conditioning and Protection, which includes a signal processing unit and a signal protection unit. 2. A multi-parameter detection device for high-voltage cables according to claim 1, characterized in that: the high-voltage cable current transformer, the offsetting impact signal unit, the intelligent charging and discharging conditioning unit, and the matching output unit are connected in sequence; The high-voltage cable current transformer obtains electric energy by inducting the cable load to supply power for the entire device; the counteracting impact signal unit limits, stabilizes, rectifies, and filters the induced current, and transmits the current into the intelligent charging and discharging conditioning unit; intelligent charging and discharging conditioning The unit adjusts the input voltage and current to match the energy sensed by the high-voltage cable current transformer in real time, so as to maintain the maximum output power; the matching output unit provides DC energy through the complete set of matching circuits. 3. A multi-parameter detection device for high-voltage cables according to claim 1, characterized in that: the temperature detection unit of the cable joint includes a fiber grating device, the fiber grating device is close to the surface of the cable joint, and the high-voltage The insulating heat shrinkable tape is wound and fixed, and the winding thickness is 5 mm; the fiber grating device includes a light source, a circulator and a fiber grating temperature sensor, the light source generates light, and the temperature signal collected by the fiber grating sensor is collected by the circulator. 4. A multi-parameter detection device for high-voltage cables according to claim 1, characterized in that: the cable bus current detection unit cable is used to detect the transmission load of high-voltage cables, which includes integral Rogowski coils and large current limiting circuits and impact The protection circuit, the cable bus current detection unit is a split structure, which includes the right piece of the cable bus current detection unit and the left piece of the cable bus current detection unit, the right piece of the cable bus current detection unit and the left piece of the cable bus current detection unit A circular through hole is formed by plugging, and a magnet is provided on the splicing surface of the right piece of the cable bus current detection unit and the left piece of the cable bus current detection unit to realize attraction. 5. A multi-parameter detection device for high-voltage cables according to claim 4, characterized in that: the cable partial discharge detection unit is used to detect high-frequency partial discharge signals of high-voltage cables, and its collection frequency range is 30KHz to 26MHz; The partial discharge detection unit includes a square high-frequency current transformer. The high-frequency current transformer is set on the cable to induce current and induce voltage in the secondary circuit; the high-frequency current transformer is equipped with a shielded shell, and the shielded shell is an open-close structure. , which includes the left piece of the cable partial discharge detection unit and the right piece of the cable partial discharge detection unit, the left piece of the cable partial discharge detection unit and the right piece of the cable partial discharge detection unit are plugged to form a square through hole, the left piece of the cable partial discharge detection unit and the cable The splicing surface of the right part of the partial discharge detection unit is provided with a magnet to realize the attraction. 6. A multi-parameter detection device for high-voltage cables according to claim 5, wherein the signal processing unit includes a cable joint temperature signal processing module, a cable bus current signal processing module, and a cable metal outer sheath grounding circulation signal processing module and cable high-frequency partial discharge signal processing module; the cable joint temperature signal processing module includes a miniature spectrometer, which outputs the received temperature signal of the temperature detection unit of the cable joint through the A output port; the cable bus current signal processing module passes through the limiter The amplitude circuit, filter circuit, protection circuit and impedance matching circuit process the cable bus load signal collected by the bus current detection unit, and then pass through the signal protection unit, and then transmit it to the data acquisition card from the B output port; the cable grounding circulation signal processing module is amplified The circuit, filter circuit and detection circuit process the cable ground circulation signal collected by the ground circulation detection unit, and then pass through the signal protection unit, and transmit it to the data acquisition card from the C output port; the cable high frequency partial discharge signal processing module passes through the limiting circuit, The filter circuit and the detection circuit process the high-frequency partial discharge signal collected by the partial discharge detection unit. With the help of the circuit protection module and the impedance matching circuit, and then through the signal protection unit, the D output port is transmitted to the data acquisition card; the cable joint temperature signal processing The module, cable bus current signal processing module, cable metal outer sheath grounding circulation signal processing module and cable high-frequency partial discharge signal processing module are protected by independent shielding boxes.