1, the introduction

In order to improve the working efficiency in the underground coal mine, the comprehensive mechanized coal mining method is adopted to raise the voltage from 1140V to 3300V, 6000V and 10KV. In order to facilitate the transmission of electric energy and input electrical equipment in production, various high and low voltage cable connectors are often used. According to the requirements of users, this paper designs and manufactures a new type of flameproof high-voltage cable connector for mining.

 

2, use

Connector is mainly suitable for coal mine with methane or coal dust explosion risk, can be imported equipment CHP33/3.3KV switch box, ID33/3.3KV cisway switch, LC33/3.3KV load switch and domestic high power switch, shift and other equipment matching use. In the line of AC FOI-IZ, 3.3 kV, current to 630A, as the power introduction device of combination switch, load switch, motor, transformer and as the coupling connection device between cable ends.

 

3. Product structure introduction

The connector consists of a plug and a socket respectively.

 

4. Technical analysis

The connector housing is made of cast tin bronze (ZCuSn6ZN6PB3). This copper alloy has good wear and corrosion resistance, easy processing, casting and gas tightness, and is very suitable for the casing and related parts of downhole cable connectors.

After finishing the shell, the hydrostatic test (hydrostatic test) is carried out at 1MPa, lasting for 1012s, and it is qualified if there is no obvious deformation that damages or affects the explosion-proof performance. The insulation of the connector is made of glass fiber reinforced unsaturated polyester molding plastic BMC for electricians. This thermosetting plastic has good mechanical and electrical properties, good heat resistance, fire resistance, dimensional stability, chemical resistance and small water absorption. Compared with other thermosetting plastics, the glass fiber reinforced unsaturated polyester molding plastics molding shrinkage rate is small, generally 0 0.5, and by changing the type and amount of low shrinkage agent to control the plastic molding shrinkage rate, to ensure the accuracy of flameproof joint and dimensional stability. Its another characteristic is a very good liquidity, low pressure molding processing can be done, but the molding process of the materials have high requirements, such as the temperature at which the suppression low, causing slow decomposition of free radicals, can cause plastic solidification, mechanical and electrical performance, physical performance will drop, so in order to get good quality parts, must strictly control the process parameters. Insulation parts made of this material can fully withstand power frequency voltage (18kV) and lightning shock voltage (20kV), in line with the requirements of the standard (MT/T947 -- 2005).

Feeder, feeder plug socket by purple copper bar after finishing processing, silver plated surface should be smooth, no bubbles, spots, defects such as peeling, feeder socket 65 mn spring steel plate after heat treatment is made of card trick on jack cylindrical, improve when connected to the feeder plug insertion force, to ensure the contact resistance of the primary loop is less than 500 fl, can reduce the temperature to rise. The general insertion force is 30-80N.

On the explosion protection structure and parameters should be in conformity with the relevant provisions of the GB3836.2-2000, due to the particularity of the connector structure with various forms of flame-proof joint surface, cylindrical connector plug for cylindrical flame-proof joint surface, the joint of socket and equipment for plane flame-proof joint surface, the plug after the precursor and body connection is threaded flame-proof joint face.

The electrical clearance and creep distance of the connector's wiring cavity part is a technical problem to be solved, which should not only ensure compliance with the requirements of GB3836.3-2000, but also minimize the size of the connector. The creepage distance is determined according to the working voltage, the anti-leakage traceability of insulating material and the surface shape of the material. The CTI of the relative leakage traceability of BMC insulating material is between 400 and 600, which belongs to the Ⅱ level and the minimum creepage distance is 45mm. We adopt the method of changing the surface shape of the parts to increase the distance to solve the problem. The minimum electrical clearance is 36mm. If this parameter is directly adopted, the size of the connector will be greatly increased. For this reason, the conductive part is completely sealed by adding a set of high voltage heat-shrinkable tubes to each conductive part, which can greatly reduce the distance between phases and thus reduce the size of the connector.

The products designed and manufactured by the above measures have been tested by Shanghai Mining Equipment Testing Center of National Safety Production, and are in full compliance with the requirements of the relevant standards, achieving the purpose of the design, and obtaining the explosion-proof qualification certificate and the safety mark license.

 

5, connector size, weight

The outer dimension of connector insert head: length 356mm x width 151mm x height 151mm

Connector socket part external dimensions: L 258mm X W 148RAMx H 164mm

Weight of connector plug: 18kg

Connector socket weight: 15kg