This standard specifies the test equipment, sample preparation, test steps, test result evaluation and precautions for DC voltage test of wires and cables. This standard is mainly applicable to DC voltage withstand test of various types of power cables and their accessories, and communication cables can also refer to it. GB/T 3048.14-1992 DC voltage test method for wires and cables GB/T3048.14-1992 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Electric cables and wires
Method for DC vollage lestThis standard adopts the relevant provisions of IEC60-1~60-4 (1973) high voltage test technology. 1 Subject content and scope of application
GH/T 3048. 14—92
This standard specifies the test equipment, sample preparation, test procedures, test result evaluation and precautions for DC voltage test of wires and cables. This standard is mainly applicable to the DC voltage withstand test of various types of power cables and their accessories, and communication cables can also be used as a reference. 2 Reference standards
GB311.2~311.6 High voltage test technologybZxz.net
GB 2900.19 Electrical terminology High voltage test technology and insulation coordination 3 Test equipment
The test equipment should meet the following requirements.
3.1 Test voltage
3.1.1 Unless otherwise specified in the product standard, the test voltage applied to the sample shall be a DC voltage with a ripple factor of no more than 5%, and the polarity of the test voltage shall be in accordance with the relevant product standards. 3.1.2 The test voltage and withstand time applied to the sample shall be in accordance with the relevant product standards. 3.2 Generation of test voltage
DC voltage is generally generated by a DC high-voltage generator. The DC high-voltage generator is mainly composed of a voltage regulator, a step-up transformer, a rectifier element, a filter capacitor, a polarity conversion device and a discharge resistor. The DC high-voltage generator should be able to output the voltage and current required for the sample test. 3.3 Measurement of test voltage
The measurement error of the average value of the test voltage shall not exceed ±3%. The average value of the test voltage shall be measured using a DC high-voltage measurement system that complies with Article 2 of GB311.4.
4 Sample preparation
4.1 For cable accessory products, unless otherwise specified in the relevant product standards. The length of the cable connected to it should generally not be less than 5m. 4.2 The sample should be under the test pressure (oil pressure or air pressure) and test temperature conditions specified in the corresponding product standard. 4.3 Before the test, the surface of the cable terminal must be wiped clean to reduce leakage current and prevent flashover discharge along its surface. When conducting DC high-voltage tests in high-temperature environments, more attention should be paid to the effect of humidity on the terminal. 5 Test steps
5.1 Wiring method:
Unless otherwise specified in the product standard, the wiring should be in the following manner. Approved by the State Administration of Industry and Information Technology on 1992-D2-19 and implemented on 1992-10-01
5. 1.1 Single-core cable
GB/T 3048.14 --- 92
The conductor is connected to the high-voltage end, and the metal sheath or shield is grounded. 5.1.2 For multi-core cables, each conductor is connected to the high-voltage end in turn, and the other conductor cabinets are interconnected and grounded together with the metal sheath, shield or armor. 5.1.3 Phase-by-phase lead (or aluminum) cable Connect each conductor to the high voltage terminal in turn, and other conductors are connected to each other and grounded together with the metal sheath, shield or package.
5.1.4 Communication cable
Refer to Table 1 for wiring.
Sample wiring method (high voltage terminal to ground terminal) Twisted element
Single core wire
Twisted pair
Three-wire group
Four-wire red
Element structure diagram
Note, a, b in the table represent the wire core conductor arrangement. No metal sheath, metal shield,
fittings and no special electrodes attached
all conductors a→
all conductors b
all conductors a—
all conductors b+core
all conductors b
all conductors a+
all conductors a+b~
all conductors c+d
all conductors ac
all conductors b+d
② In the table, 0 represents metal sheath, metal shield, fittings or special electrodes attached. ③ In the table, \\ represents mutual electrical connection, @① additional electrodes refer to water sugar, metal beads, stone coating, wrapped metal box, etc. With metal sheath, metal screen,
armor or additional special electrode
Each conductor is connected to all other conductors and
metal sheath, screen, armor and ground
All conductors→
All conductors b
All conductors a+b-+0
All conductors a-
All conductors b+core
hAll conductors b-
All conductors a+c
All conductors a+b+c-0
All conductors a+b-→
All conductors cd
All conductors a+c-
All conductors b+d
All conductors a+b+c+d-0
③Other wiring methods are allowed, but it must be ensured that each core of the sample is subjected to the true current voltage test required by the product standard. 5.1.5 When testing the insulating sheath between the metal sheath (shield) and armor of the sample, all conductors should be connected to the metal sheath (shield) and connected to the high voltage terminal, and the armor should be connected to the ground terminal. 5.1.6 When testing the insulating sheath (without armor) outside the metal sheath (shield) of the sample, all conductors should be connected to the metal (shield) and connected to the high voltage terminal, and the additional electrode (such as a sink or other electrode) should be connected to the ground terminal. 5.1. When testing the insulating sheath outside the test equipment, all conductors should be connected to the metal sheath (shield) and armor, and connected to the high voltage terminal, and the additional electrode (such as a water tank or other electrode) should be connected to the ground terminal. 5.2 Unless otherwise specified in the product standard, the test is generally carried out at the ambient temperature of the test site, and the difference between the temperature of the sample and the ambient temperature should not exceed ±3.
GB/T 3048. 14—92
5.3 The voltage applied to the sample should start from a lower value (should not exceed 40% of the test voltage value specified in the corresponding product standard), and slowly and steadily rise to the specified test voltage value so that it can be accurately read on the instrument. After the test voltage value is maintained for a specified time, the voltage is slowly reduced until it is below 40% of the specified test voltage value, and then the power supply is cut off, and the high-voltage end of the sample is grounded through the discharge resistor with an insulating grounding rod. The resistance of the discharge resistor is selected according to the corresponding test voltage, generally not less than 10k/kV. The resistor should be able to withstand the test voltage applied to the sample without flashover discharge, and can withstand the discharge energy without overheating. 5.4 The voltage deviation of the test voltage applied to the sample should not exceed ±3% of the corresponding test voltage value during the withstand voltage time. 6 Evaluation of test set
6.1 If the sample has no flashover discharge during the application of the corresponding specified test voltage and duration, or the test circuit current does not increase with time, the sample can be considered to have passed the withstand DC voltage test. If the current increases sharply during the test, and the line switch of the DC high-voltage generator trips, or the sample cannot withstand the specified test voltage again, the sample can be considered to have broken down. 7 Precautions
7.1 The DC high-voltage generator should have a fast overcurrent protection device to ensure that the test power supply can be quickly cut off when the sample breaks down or the sample end or terminal head has a flashover discharge along its surface or internal breakdown. 7.2 The test area should be surrounded by metal grounding fences, interlocking of import and export doors, signal indicators and "high voltage danger" warning signs and other safety measures. 7.3 There should be a grounding electrode in the test area, and the grounding resistance should be less than 4. The grounding terminal of the DC high-voltage generator and the grounding terminal of the sample should be reliably connected to the grounding electrode.
7.4 A sufficient safety distance should be maintained between the DC high-voltage terminal (including the DC high-voltage generator, measuring device and sample) and the surrounding grounding body: to prevent air discharge
7.5 All equipment that is easily induced and charged near the DC high-voltage terminal (including the DC high-voltage generator, measuring device and sample) should be reliably grounded. Additional remarks:
This standard is proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the Shanghai Cable Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Upstream Electric Research Institute of the Ministry of Machinery and Electronics Industry, etc. The main drafter of this standard is Yang Wencai.
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