Testing method for evaluating the bonding degree between composite insulator sheath and core rod

Abstract

The present invention relates to the field of power detection technology, and is a detection method for evaluating the degree of combination between a composite insulator sheath and a core rod, comprising: placing a composite insulator sample horizontally in a salt spray test chamber, and connecting the composite insulator sample to a leakage current measuring device and a high-voltage power supply respectively; the leakage current detection device determines whether all leakage currents are less than a preset current value, and responds if so, the interface of the composite insulator short sample is qualified, and responds if not, the interface of the composite insulator short sample is unqualified. The present invention places the composite insulator sample horizontally in a salt spray test chamber, uses a high-voltage power supply to output a high-voltage current, and the leakage current detection device determines whether the interface of the composite insulator short sample is qualified according to the leakage current, which not only sensitively reflects and identifies the interface defects of the composite insulator, but also solves the problem of the existing detection method of placing the insulator core rod obliquely and then dripping a salt solution at one end of the composite insulator short sample that the salt solution drops rapidly for a long time and easily causes a short circuit.

Description

Technical Field

[0001] The invention relates to the technical field of electric power detection, in particular to a detection method for evaluating the degree of combination between a composite insulator sheath and a core rod. Background Art

[0002] The interface of the composite insulator is located on the inner side of the insulator sheath and is bonded to the internal core rod. If there are defects inside, it is difficult to find. It is not easy to detect during factory inspection, random inspection and line inspection. When the internal defects develop to a large extent under the influence of electric field strength and external natural environmental factors, they will gradually show characteristics such as heating on the outside. The existence of this defect will further reduce the mechanical bearing capacity of the composite insulator, and the electrical performance of the insulator material itself will also decrease. Therefore, the composite insulator interface detection is carried out in the early stage of defect formation, which can prevent the defects from further deepening to a certain extent and improve the operation stability of the insulator.

[0003] At present, the interface detection method of composite insulators is mainly the interface test of sheathed core rods, but this method has not formed a standard, and only random sampling tests are carried out when purchasing samples, and no specific criteria are given for the operation stage of the transmission line. For example, Chinese patent CN107797036B discloses a composite insulator interface defect detection method based on high voltage and salt solution evaluation. This detection method performs a high voltage test on the composite insulator and measures the leakage current data. It mainly takes into account that the insulator core rod is placed obliquely, there is no umbrella skirt, the sheath and the core rod form a cylindrical surface, and the long-term rapid drop of the salt solution is easy to cause a short circuit, which is not practical. Chinese patent CN102507731A discloses a composite insulator interface defect detection method, which selects the leakage current change rate of the composite insulator sample before and after boiling as an indicator, and quickly and efficiently completes the interface performance evaluation of the sample. However, the comparison of the leakage current data before and after the boiling test of this method does not have obvious characteristics and the coupling relationship, and the leakage current measurement data is small, lacking reliable data support. Summary of the invention

[0004] The present invention provides a detection method for evaluating the degree of bonding between a composite insulator sheath and a core rod, which overcomes the above-mentioned shortcomings of the prior art and can effectively solve the problems existing in the prior art based on high voltage and salt solution to evaluate composite insulator interface defect detection methods, such as the insulator core rod being placed obliquely, having no shed skirt, the sheath and the core rod forming a cylindrical surface, and the salt solution falling rapidly for a long time and easily causing a short circuit.

[0005] One of the technical solutions of the present invention is achieved by the following measures: A detection method for evaluating the bonding degree between a composite insulator sheath and a core rod comprises:

[0006] The composite insulator sample is placed horizontally in the salt spray test chamber, and the composite insulator sample is connected to the leakage current measuring device and the high voltage power supply respectively;

[0007] The high voltage power supply is powered on, and the leakage current detection device detects the leakage current of the composite insulator sample;

[0008] The leakage current detection device determines whether all leakage currents are less than a preset current value, and if so, the interface of the short composite insulator sample is qualified, and if not, the interface of the short composite insulator sample is unqualified.

[0009] The following are further optimizations and / or improvements to the above technical solutions:

[0010] The above-mentioned salt spray test chamber can spray mist droplets. The solution in the salt spray test chamber is a 0.1% mass concentration solution of NaCl, and the spray pressure adjustment range is 0.4 to 1.2 kg / cm3.

[0011] After pretreatment, the composite insulator sample is placed horizontally in a salt spray test chamber, and the high-voltage end of the composite insulator sample is connected to a high-voltage power supply, and the low-voltage end is grounded after passing through a leakage current measuring device.

[0012] The high voltage AC voltage value output by the above-mentioned high voltage power supply is 10 to 30 kV.

[0013] The length of the composite insulator sample is 200 to 300 mm; the length of the exposed core rods at both ends of the composite insulator is 20 mm; and the middle section is the length of the sheath portion.

[0014] The invention is simple to use. The composite insulator sample is horizontally placed in a salt spray test box, and the composite insulator sample, a leakage current measuring device, and a high-voltage power supply form a high-voltage loop. The high-voltage power supply outputs a high-voltage current, and the leakage current detection device detects the leakage current of the composite insulator sample. The interface of the short composite insulator sample is judged to be qualified according to the leakage current. The invention can not only sensitively reflect and identify the composite insulator interface defects, but also accurately judge whether the composite insulator interface defects exist. At the same time, the invention overcomes the problem that it is difficult to sensitively reflect the composite insulator interface defects by using a withstand voltage test and a steep wave impact test, and further solves the problem that the salt solution in the existing detection method of tilting the insulator core rod and then dripping a salt solution at one end of the short composite insulator sample is prone to short circuit due to long-term rapid drop of the salt solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 It is a connection diagram for use of the present invention.

[0016] Attached Figure 2 The present invention is a flow chart of a method.

[0017] Attached Figure 3 The present invention is another method flow chart. DETAILED DESCRIPTION

[0018] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0019] The present invention will be further described below in conjunction with embodiments and drawings:

[0020] Embodiment 1: As attached Figure 1 , 2 As shown, the embodiment of the present invention discloses a detection method for evaluating the bonding degree between a composite insulator sheath and a core rod, comprising:

[0021] Step S101, placing the composite insulator sample horizontally in a salt spray test chamber, and connecting the composite insulator sample to a leakage current measuring device and a high voltage power supply respectively;

[0022] Step S102, the high voltage power supply is powered on, and the leakage current detection device detects the leakage current of the composite insulator sample;

[0023] Step S103, the leakage current detection device determines whether all leakage currents are less than a preset current value, and if so, the interface of the short composite insulator sample is qualified, and if not, the interface of the short composite insulator sample is unqualified.

[0024] In the above embodiment, both ends of the composite insulator sample are exposed core rod parts, and the length of the composite insulator sample can be 200 to 300 mm, the length of the exposed core rods at both ends of the composite insulator can be 20 mm, and the middle section is the length of the sheath part. In step S101, the composite insulator sample is placed in a salt spray test chamber, and the composite insulator sample is connected to a leakage current measuring device and a high-voltage power supply respectively, so that the composite insulator sample and the leakage current measuring device are connected in series to form a loop with the high-voltage power supply, and the high-voltage power supply can pass the high-voltage current through one end of the composite insulator sample to the composite insulator sample. In step S102, the leakage current detection device detects the leakage current of the composite insulator sample. Since the detection content of the leakage current detection device in this embodiment includes detecting the hidden defects of the interface between the core rod and the sheath of the non-exposed part of the composite insulator sample, the leakage current detection device needs to detect all leakage currents of the composite insulator sample. The preset current value in step S103 is a current value set according to the type of the composite insulator sample. The leakage current detection device determines whether all leakage currents are less than the preset current value. If the response is yes, the interface of the short composite insulator sample is qualified. If the response is no, the interface of the short composite insulator sample is unqualified.

[0025] In the above embodiment, the high voltage AC voltage output by the high voltage power supply is 10 to 30 kV; mist droplets can be sprayed in the salt spray test chamber, the solution in the salt spray test chamber is a 0.1% mass concentration solution of NaCl, and the spray pressure adjustment range is 0.4 to 1.2 kg / cm3.

[0026] In summary, the embodiment of the present invention discloses a detection method for evaluating the degree of bonding between the composite insulator sheath and the core rod, wherein the composite insulator sample is horizontally placed in a salt spray test chamber, and the composite insulator sample, a leakage current measuring device, and a high-voltage power supply form a high-voltage circuit, and the high-voltage power supply is used to output a high-voltage current, and the leakage current detection device detects the leakage current of the composite insulator sample, and the interface of the short composite insulator sample is judged to be qualified according to the leakage current, which can not only sensitively reflect and identify the composite insulator interface defects, but also accurately judge whether the composite insulator interface defects exist. At the same time, it overcomes the problem that it is difficult to sensitively reflect the composite insulator interface defects by using a withstand voltage test and a steep wave impact test, and further solves the problem that the salt solution in the existing detection method of tilting the insulator core rod and then dripping a salt solution at one end of the short composite insulator sample is prone to short circuit due to long-term rapid drop of the salt solution.

[0027] Embodiment 1: As attached Figure 1 , 3 As shown, the embodiment of the present invention discloses a detection method for evaluating the bonding degree between a composite insulator sheath and a core rod, comprising:

[0028] Step S201, after pretreatment, the composite insulator sample is placed horizontally in a salt spray test chamber, and the high voltage end of the composite insulator sample is connected to a high voltage power supply, and the low voltage end is grounded after passing through a leakage current measuring device;

[0029] Step S202, the high voltage power supply is powered on, and the leakage current detection device detects the leakage current of the composite insulator sample;

[0030] Step S203, the leakage current detection device determines whether all leakage currents are less than a preset current value, and if so, the interface of the short composite insulator sample is qualified, and if not, the interface of the short composite insulator sample is unqualified;

[0031] Step S204, performing interface grading on the short composite insulator samples.

[0032] In step S201 of the above embodiment, the composite insulator sample is pretreated and then placed horizontally in a salt spray test chamber. The pretreatment includes preparing the composite insulator sample for sampling before testing, boiling it in water for a set time (e.g., 48 hours), and then drying it within a specified time. At the same time, it is placed horizontally in the salt spray test chamber for a set time (e.g., 6 hours).

[0033] In step S204 of the above embodiment, the interface classification of the short composite insulator samples with qualified interfaces is specifically performed as follows:

[0034] 1. Set a preset current value, and set the current threshold corresponding to each interface level in combination with the preset current value. For example, the preset current value is 100μA; if the leakage current is less than 50μA, the interface is level 1; if the leakage current is less than 50 to 100μA, the interface is level 1; if the leakage current is greater than 100μA, the interface of composite insulator sample 1 is level 3;

[0035] 2. Compare the leakage current with the set current threshold, and determine the interface grade of the composite insulator short sample according to the comparison result. When the interface of the composite insulator sample is level one or level two, it is qualified and meets the use requirements; when the interface of the composite insulator sample is level three, it is unqualified and does not meet the use requirements.

[0036] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A detection method for evaluating the bonding degree between a composite insulator sheath and a core rod, characterized in that: include: After pretreatment, the composite insulator samples were placed horizontally in a salt spray test chamber, and the composite insulator samples were connected to a leakage current measuring device and a high-voltage power supply, respectively. The pretreatment included preparing the composite insulator samples for sampling before testing, boiling them in water for a set time, and then drying them within a specified time. The salt spray test chamber can spray mist droplets. The solution in the salt spray test chamber is a 0.1% mass concentration solution of NaCl, and the spray pressure adjustment range is 0.4 to 1.2 kg / cm 3 ; The high voltage power supply is powered on, and the leakage current detection device detects the leakage current of the composite insulator sample; The leakage current detection device determines whether all leakage currents are less than a preset current value, and if so, the interface of the short composite insulator sample is qualified, and if not, the interface of the short composite insulator sample is unqualified.

2. The detection method for evaluating the bonding degree between the composite insulator sheath and the core rod according to claim 1 is characterized in that: The high voltage AC voltage output by the high voltage power supply is 10 to 30 kV.

3. The detection method for evaluating the bonding degree between the composite insulator sheath and the core rod according to claim 1 or 2, characterized in that: The length of the composite insulator sample is 200 to 300 mm; the length of the exposed core rods at both ends of the composite insulator is 20 mm; and the middle section is the length of the sheath portion.

Images