CN-115902554-B - Multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device and method

Abstract

The present invention discloses a device and method for simulating the electromagnetic distribution characteristics of overlapping states of multi circuit distribution cables, comprising a power frequency source, a phase modulation unit, a current boosting unit, a high-frequency signal coupling unit, multiple cable segments, multiple cable overlapping units, a control unit, and an electromagnetic signal measurement unit. The device adopts a modular design and can simulate different cable overlapping states of multiple segments simultaneously by simply changing the position of the cable connection plug. It can also apply different current loads and high-frequency signals simultaneously, and can achieve real simulation of cable groups in cable trenches.

Inventors

• HOU ZHE
• ZHAO XUEFENG
• YANG CHUANKAI
• REN SHUANGZAN
• SUN HAOFEI
• DUAN WEI
• WANG CHENXI
• LIU JIAOJIAN
• YANG BO
• JU ZELI
• TENG SEN
• SHANG YU
• Yun Xiahaoyue
• CAI WENCHENG
• GONG MINGCHAO
• PU LU

Assignees

• 国网陕西省电力有限公司电力科学研究院
• 国网(西安)环保技术中心有限公司

Dates

Publication Date

20260508

Application Date

20221222

Claims (9)

1. 1. The multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device is characterized by comprising a phase modulation unit, an up-flow unit, a high-frequency signal coupling unit, a cable and an electromagnetic signal measuring unit, wherein the cable comprises n cable sections connected through the cable overlapping unit; The input end of the phase modulation unit is used for connecting a power frequency power supply, the output end of the phase modulation unit is connected with the primary side of the current rising unit, the secondary side of the current rising unit is connected with the head end of a cable through the high-frequency signal coupling unit, the tail end of the cable is connected with the secondary side of the current rising unit, the cable comprises n cable sections and a cable overlapping unit connected with the n cable sections, and an electromagnetic signal measuring unit is arranged on each cable section; The cable overlapping unit comprises an insulating panel (14), wherein the insulating panel (14) is of a multi-layer structure, each layer is provided with a sliding guide rail (9), a rotatable disc surface is arranged on each sliding guide rail (9), each rotatable disc surface comprises a base (7) and a rotary disc (8) rotatably arranged on the base (7), connectors are arranged at two ends of each rotatable disc surface, the connectors can be rotated on a plane by the rotatable disc surface, and each connector comprises a three-phase wire core plug (12), a metal coaxial shielding structure (15) and a rubber layer (13) which are sequentially arranged from inside to outside.
2. 2. The multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device according to claim 1, wherein the current rising unit comprises a three-phase through-core transformer, a three-phase metal guide rod (3), an insulating support piece, an electromagnetic shielding box body (5), a first end wire core plug (21) and a second end wire core plug (22), and the three-phase through-core transformer, the three-phase metal guide rod (3) and the insulating support piece are all arranged in the electromagnetic shielding box body (5); The metal guide rod (3) both ends all are provided with first end sinle silk plug (21) and second end sinle silk plug (22) that are used for connecting cable head and tail both ends respectively, and first end sinle silk plug (21) and second end sinle silk plug (22) pass the lateral wall of electromagnetic shield box (5), and metal guide rod (3) pass first insulating support piece (41), second insulating support piece (42) and third insulating support piece (43), all install the through type transformer on three-phase metal guide rod (3).
3. 3. The multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device according to claim 2, wherein the first insulating support (41), the second insulating support (42) and the third insulating support (43) are respectively located at the head end, the middle part and the tail end of the metal guide rod (3) and play a supporting role on the metal guide rod (3).
4. 4. The multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device is characterized in that the high-frequency signal coupling unit comprises a high-frequency signal generating unit, a capacitive coupling sensor (16) and a coaxial metal shield (6), the coaxial metal shield (6) is coated outside a metal guide rod (3) of the current rising unit, the capacitive coupling sensor (16) is arranged in the coaxial metal shield (6), the three-phase capacitive coupling sensors (16) are connected to the high-frequency signal generating unit, and the high-frequency signal generating unit is used for generating high-frequency electromagnetic signals simulating a cable channel site.
5. 5. The multi-circuit distribution cable overlapping state electromagnetic distribution characteristic simulation device according to claim 1, wherein the insulating panel (14) is provided with a clamping lock (10) for fixing the position of the rotatable disc surface.
6. 6. The multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device according to claim 1, wherein the core plug (12) is made of metal, and the turntable (8) is made of insulating materials.
7. 7. A method for simulating electromagnetic distribution characteristics of a multi-loop distribution cable in an overlapping state, based on the device of claim 1, comprising the following steps: S1, setting the total loop number of a distribution cable in an analog cable channel as m, stripping and separating the head end three phases of a cable section 1 of each loop, butting a three-phase conductor (11) with a high-frequency signal coupling unit, stripping and separating the tail end three phases of a cable section n of each loop, and butting the three-phase conductor (11) with the secondary side of a current rising unit; s2, butting the cable sections of each loop through a cable overlapping unit, and changing positions of the cable sections on two sides of the cable overlapping unit according to test requirements; s3, converting the three-phase power frequency voltage with 120-degree phase difference into m groups of three-phase voltages with different initial phases phi by the phase modulation unit, and respectively connecting the phase-modulated voltages to m A, B, C three-phase core-through transformers in the current rising unit; The high-frequency signal coupling unit generates a required high-frequency signal, and the generated signal is coupled into the cable core through the capacitive coupling sensor (16); S4, different cable overlapping forms are arranged in each cable section, different currents with different magnitudes flow in each loop of cable to carry different types of high-frequency signals, and in each cable section, signal measurement is carried out on different positions or positions which are actually required by a rogowski coil, a capacitive coupler, an ultrahigh frequency sensor and/or an electric wave sensor.
8. 8. The method for simulating electromagnetic distribution characteristics of a multi-loop power distribution cable overlapping state according to claim 7, wherein when cable electricity test research is carried out, no up-flow signal is applied to one loop of cables, pulse signals are applied to the loop of cables only through a path meter, other loops are normally up-flowed, higher harmonic signals, random noise signals and/or partial discharge signals are coupled in the other loops, the overlapping condition of cable sections and the characteristics of other phase applied signals are changed by utilizing a cable overlapping unit, and the signal characteristics of the loops without the up-flow signals are detected by high-frequency CT.
9. 9. The method for simulating electromagnetic distribution characteristics of overlapping states of multi-loop distribution cables according to claim 7, wherein when partial discharge interference test is performed, the overlapping states of different cables are changed by using a cable overlapping unit, different discharge signal types are set, different noise interference is set by using a high-frequency signal coupling unit, and then partial discharge signals are measured by using an ultrahigh frequency sensor.

Description

Multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device and method Technical Field The invention belongs to the technical field of distribution cable detection, and particularly relates to an electromagnetic distribution simulation device and method under a multi-loop distribution cable overlapping state. Background Medium voltage distribution cables are key devices in urban distribution networks and industrial power transmission networks. However, due to field installation process problems and severe laying environments, the insulation of the distribution cable may gradually deteriorate during operation, eventually resulting in an accident caused by insulation breakdown. In order to ensure safe and reliable operation of the cable, workers often detect or test the cable by adopting a live or power-off means. If the detection signal is electrified, electromagnetic interference of surrounding space (other running cables in a cable trench) is often received, if the detection signal is in power failure detection, whether the cable is electrified or not is required to be judged according to safety regulations, high-frequency electromagnetic pulse coupling signals are often adopted as judging means, and the judgment means are also often subjected to the surrounding electromagnetic interference, so that misjudgment and personal safety accidents are possibly caused. However, the environment in the cable channel is very complex, and the distribution cables of different loops are mutually overlapped, if the electromagnetic signals in the cable channel in the complex environment are not subjected to corresponding simulation analysis, the electromagnetic interference characteristics under the condition of multi-cable overlapping are mastered, and larger interference can be caused to field detection. Disclosure of Invention The invention provides a multi-loop distribution cable overlapping state electromagnetic distribution characteristic simulation device and method, which can simulate multi-section different cable overlapping states at the same time and realize the real simulation of a cable group in a cable channel. The invention provides an electromagnetic distribution characteristic simulation device for a multi-loop power distribution cable overlapping state, which comprises a phase modulation unit, a current rising unit, a high-frequency signal coupling unit, a cable and an electromagnetic signal measuring unit, wherein the cable comprises n cable sections connected through the cable overlapping unit, the input end of the phase modulation unit is used for being connected with a power frequency power supply, the output end of the phase modulation unit is connected with the primary side of the current rising unit, the secondary side of the current rising unit is connected with the head end of the cable through the high-frequency signal coupling unit, the tail end of the cable is connected with the secondary side of the current rising unit, the cable comprises n cable sections and overlapping units connected with the n cable sections, and the electromagnetic signal measuring unit is arranged on each cable section. Further, the current rising unit comprises a three-phase through type transformer, a three-phase metal guide rod, an insulating support piece, an electromagnetic shielding box body, a first end wire core plug and a second end wire core plug, wherein the three-phase through type transformer, the three-phase metal guide rod and the insulating support piece are all arranged in the electromagnetic shielding box body; The metal guide rod is provided with a first end wire core plug and a second end wire core plug which are used for connecting the head end and the tail end of the cable respectively, the first end wire core plug and the second end wire core plug penetrate through the side wall of the electromagnetic shielding box body, the metal guide rod penetrates through the first insulating supporting piece, the second insulating supporting piece and the third insulating supporting piece, and the penetrating type transformer is arranged on the three-phase metal guide rod. Further, the first insulating support piece, the second insulating support piece and the third insulating support piece are respectively positioned at the head end, the middle part and the tail end of the metal guide rod and play a role in supporting the metal guide rod. Further, the high-frequency signal coupling unit comprises a high-frequency signal generating unit, a capacitive coupling sensor and a coaxial metal shield, wherein the coaxial metal shield is coated outside a metal guide rod of the current rising unit, the capacitive coupling sensor is arranged in the coaxial metal shield, three-phase capacitive coupling sensors are connected to the high-frequency signal generating unit, and the three-phase high-frequency signal generating unit is used for generating high-frequency electr