3. 1, insulation tools:
3. 1. 1, hard insulation tool:
Mainly refers to the power distribution network live working tools made of epoxy resin glass fiber reinforced insulating tubes, plates and rods as the main insulating materials. Including work tools, vehicles, load-bearing tools, etc. And insulated operating rods with different metal tools at the ends.
3. 1.2, soft insulation tool:
Mainly refers to tools made of insulating materials, including lifting tools and load-bearing tools.
3. 1.3, insulated bucket arm car:
Mainly refers to the tool used to adjust the position of live workers in the live operation of distribution network, which is made of insulating material.
3.3, safety protection equipment:
3.3. 1, insulating gloves:
Refers to gloves that play an electrical insulation role in live working of distribution network, and are made of synthetic rubber or natural rubber. Its shape is divided into fingers.
3.3.2, insulating boots:
Refers to the boots that play the role of electrical insulation in the live operation of distribution network, and are made of synthetic rubber or natural rubber.
3.3.3, insulating clothing, shawls, cuffs, bra:
Refers to the wearing appliance made of rubber or other insulating flexible materials, which is a safety protection appliance to protect workers from electric shock when contacting live conductors and electrical equipment. Electrical safety performance testing instruments-withstand voltage tester, leakage current tester, insulation resistance tester and grounding resistance tester. 1. The compressive strength of withstand voltage tester can also be called compressive strength, dielectric strength and dielectric strength. The highest electric field strength that an insulating substance can withstand without being damaged is called compressive strength. During the test, when the tested sample reaches the specified time under the required test voltage, withstand voltage tester automatically or passively cuts off the test voltage. Once the breakdown current exceeds the set breakdown (protection) current, it can automatically cut off the test voltage and give an audible and visual alarm. So as to ensure that the tested sample is not damaged. Mainly achieve the following purposes: 1. Test the insulation's ability to withstand working voltage or overvoltage. Two. Check the insulation manufacturing or maintenance quality of electrical equipment. Three. Eliminate the damage of raw materials, processing or transportation to insulation and reduce the early failure rate of products. Four. Check the electrical gap and creepage distance of insulation. Withstand voltage tester is an instrument for measuring the withstand voltage of various electrical devices, insulation materials and insulation structures. The instrument can adjust the required AC (or DC) test voltage and set the breakdown (protection) current. In the test, when the sample reaches the specified time under the required test voltage, withstand voltage tester automatically or passively cuts off the test voltage; Once the breakdown occurs and the current exceeds the set breakdown (protection) current, the output can be automatically cut off, and an alarm will be given at the same time to judge whether the sample can withstand the specified insulation strength test. It can intuitively, accurately, quickly and reliably test the electrical safety performance indexes of various tested objects, such as voltage, breakdown voltage, leakage current, etc. And can carry out different forms of dielectric performance tests such as power frequency and DC, surge and shock wave under the test conditions specified by IEC or national safety standards. At home and abroad, such instruments have different names such as withstand voltage tester, Dielectric Breakdown Device, withstand voltage tester, Surge Insulation Tester and High Voltage Tester. The history of the prototype of withstand voltage tester, the high-voltage tester, can be traced back to a long time ago, but it was in the late 1970s, after the worldwide promotion of safety standards. In the mid-1950s, typical products with timing control and leakage current testing functions, such as UPU- 1 dielectric breakdown tester in the former Soviet Union, were all single-range electron tube circuits, which were mainly used to test the electrical strength of electrical insulation materials. At the end of 1970s, with the announcement of IEC65, Japanese Jushui Company developed TOS8000 series withstand voltage tester, which used transistors and integrated circuits. The technical documents clearly point out that its products are designed to meet the requirements of IEC, JIS, UL and other safety standards. In the early 1980s, IEC664( 1980) issued the new regulations for standard pulse wave withstand voltage test for the first time, and HAEFELY Company of Switzerland immediately developed the P 12 shock wave withstand voltage tester. It can be seen that the development of basic safety testing instruments and safety standards is synchronous and inseparable. Second, the insulation resistance tester The insulation resistance tester is an instrument used to measure insulation resistance. Insulation resistance refers to the resistance between two conductors separated by insulating materials, which is called insulation resistance. In order to ensure the safe operation of electrical equipment, minimum requirements should be put forward for insulation resistance between conductors with different polarities (different phases) or between conductors and shell. For example, household appliances and similar appliances stipulate that the basic insulation is 2MW and the reinforced insulation is 7MW. The factors that affect the measured value of insulation resistance are: temperature, humidity, measuring voltage and action time, residual charge in winding and insulation surface condition. By measuring the insulation resistance of electrical equipment, the following purposes can be achieved: a. Understand the insulation performance of the insulation structure. A reasonable insulation structure (or insulation system) composed of high-quality insulation materials should have good insulation performance and high insulation resistance; B. Understand the insulation treatment quality of electrical products. The insulation treatment of electrical products is not good, and the insulation performance is obviously reduced; Understand insulation humidity and pollution. When the insulation of electrical equipment is wet and polluted, its insulation resistance usually drops obviously; D. check whether the insulation can withstand the withstand voltage test. If the withstand voltage test is carried out when the insulation resistance of electrical equipment is lower than a certain limit, a large test current will be generated, which will cause thermal breakdown and damage the insulation of electrical equipment. Therefore, usually all kinds of test standards stipulate that insulation resistance should be measured before withstand voltage test. Third, the leakage current tester leakage current refers to the current formed between metal parts that are insulated from each other in electricity, or between live parts and grounding parts, through the surrounding medium or insulating surface without the application of fault voltage, which is called leakage current. According to the American UL standard, leakage current is a current that can be conducted from the contactable part of household appliances, including capacitive coupling current. The leakage current includes two parts, one is the conduction current I1through the insulation resistance; The other part is the displacement current I2 through the distributed capacitor. The capacitive reactance of the latter is XC= 1/2pfc, which is inversely proportional to the power frequency. The distributed capacitor current increases with the increase of frequency, so the leakage current increases with the increase of power frequency. For example, if the power supply is provided by a silicon controlled rectifier, its harmonic component will increase the leakage current. If the insulation performance of a circuit or system is evaluated, this current should not only include all currents flowing into the earth (or the conductive part outside the circuit) through insulating substances, but also include currents flowing into the earth through capacitive devices (distributed capacitors can be regarded as capacitive devices) in the circuit or system. Longer wiring will form larger distribution capacity and increase leakage current, so special attention should be paid in ungrounded systems. The principle of measuring leakage current is basically the same as that of measuring insulation resistance, which is actually a kind of leakage current, only expressed in the form of resistance. However, AC voltage is used for normal measurement of leakage current, so the component of leakage current includes capacitive component. In the withstand voltage test, in order to protect the test equipment and carry out the test according to the specified technical indicators, it is also necessary to determine the maximum current value that can flow through the tested equipment (insulating material) without destroying the highest electric field strength of the tested equipment (insulating material). This kind of current is often called leakage current, but this method is only used in the above specific cases. Please pay attention to the difference. Leakage current is actually the current that flows through the insulation part of electrical circuit or equipment without fault and applied voltage. Therefore, it is one of the important signs to measure the insulation of electrical appliances and the main index of product safety performance. Limiting the leakage current to a small value plays an important role in improving the safety performance of products. The leakage current tester is used to measure the leakage current irrelevant to the work generated by the working power supply (or other power supply) of electrical appliances through insulation or distributed parameter impedance, and its input impedance simulates the human impedance. The leakage current tester is mainly composed of impedance transformation, range transformation, AC DC transformation, amplification, indicating device and so on. Some also have over-current protection, acousto-optic alarm circuits and test voltage regulating devices, and their indicating devices are divided into analog and digital. Fourth, grounding resistance The word "grounding resistance" is an unclear word. In some standards (such as household appliances safety standards), it refers to the grounding resistance inside the equipment, while in some standards (such as grounding design specifications), it refers to the resistance of the whole grounding device. What we are talking about is the grounding resistance inside the equipment, that is, the grounding resistance mentioned in the general product safety standards (also called grounding impedance), which reflects the resistance between the exposed conductive part of the equipment and the total grounding terminal of the equipment. The general standard stipulates that the resistance should not be greater than 0.1w. Grounding resistance means that once the electrical insulation fails, the easily accessible metal parts such as the electrical shell may be charged, which requires reliable grounding to protect the safety of electrical users. Grounding resistance is an important index to measure the reliability of electrical grounding protection. Grounding resistance tester The grounding resistance can be measured with a grounding resistance tester. Because the grounding resistance is very small, usually tens of milliohms, it is necessary to use four-terminal measurement to eliminate the contact resistance in order to get accurate measurement results. The grounding resistance tester consists of a test power supply, a test circuit, an indicator and an alarm circuit. The test power supply generates 25A (or 10A) AC test current. The test circuit amplifies and converts the voltage signal obtained by the tested electrical appliance, which is displayed by the indicator. If the measured grounding resistance is greater than the alarm value (0. 1W or 0.2W), the instrument will give an audible and visual alarm.