1、 Purpose:
GW4-27.5T (D) (W) outdoor AC high voltage isolation switch for electrified railways is an outdoor high voltage electrical equipment with a frequency of 50HZ, used for switching AC 27.5kV contact network high voltage lines under voltage and no-load conditions, as well as for electrically isolating high-voltage busbars, circuit breakers and other electrical equipment under maintenance from live high voltage lines. It can also be used to separate and combine very small capacitor currents and inductor currents.
2、 Environmental conditions for use
1. Altitude not exceeding 1000m; 2000m
2. Environmental temperature: upper limit+40 ℃, lower limit -30 ℃;
3. Wind speed not exceeding 35m/s;
4. The seismic intensity shall not exceed 8 degrees;
5. Insulator pollution level: Anti pollution type is Class III heavy pollution (salt density 0.3 milligrams per square centimeter);
6. Installation location: Outdoor concrete single pole pole.

4、 Structure
The GW4-27.5T (D) (W) type outdoor AC high voltage isolation switch for electrified railways has reliable performance, simple structure, flexible installation method, easy maintenance, wide applicability, and strong versatility.
The GW4-27.5T outdoor isolation switch is a high-voltage electrical device composed of a single pole isolation switch, and is also a basic unit derived from other structures. It is referred to as a common isolation switch below.
W4-27.5T (D) outdoor isolation switch is made by adding a grounding knife to a regular isolation switch, which is divided into two types: one-time operation type and double operation type, hereinafter referred to as grounding type isolation switch.
The GW4-27.5T (D) W outdoor isolation switch is a modification of the ordinary rod type post insulator into an anti fouling rod type post insulator based on the ordinary (grounding) isolation switch, and is suitable for heavily polluted or high-altitude areas.
1. Isolation switch structure
The single pole isolation switch is fixed on the same chassis by two rod type post insulators, and is a double column horizontal rotary structure. The external structure is shown in Figure 1.

Each pole isolation switch consists of a base, an insulating pillar, and a conductive part.
Each pole isolation switch has two insulation pillars fixed on the bearings at both ends of the base (Figure 2), connected by connecting rods. Each insulation pillar can rotate horizontally at a 90 ° angle, and is equipped with a conductive terminal block (Figure 3) and left and right contacts (Figure 4). The left and right contacts make contact between two insulated pillars through a conductive tube.
The conductive terminal block is divided into two types based on its structure: hard connection type (Figure 3a) and connection type (Figure 3b), which are determined according to the user's ordering requirements.
The material of the conductive circuit components in the main circuit is copper, and when the current level is 630A, the surface of the conductive components is tin plated; When the current level is above 1600A, the surface of conductive components is silver plated.
The middle contact is a "handshake" structure, which adopts patented technology for pressing the contact finger blade gasket. It is a high-pressure, self-cleaning type, and the contact pressure of the contact finger remains constant for a long time. The contact finger spring has no current passing through, and it operates safely and reliably for a long time.
The structural types, bases, post insulators, and other components of products with different current specifications are the same, except for slight differences in the main electrical circuit

The base part is shown in Figure 2

1. Mechanical interlocking between single grounding secondary operation isolation switch and grounding switch blade
The mechanical interlocking between the single grounding secondary operation isolation switch and the grounding switch blade is achieved through the interlocking panel on the CS8-6D manual mechanism.
2. Structure of manual mechanism
This series of isolating switches is equipped with two manual mechanisms: CS11 (ungrounded and single grounded one-time operation transmission type) and CS8-6D (single grounded secondary operation transmission type).
CS11 (see Figure 6) and CS8-6D manual mechanisms (see Figure 7) have a horizontal rotation handle with a rotation angle of 90 °.
4. Structure of CX-6 electric mechanism
The structure of the CX-6 electric mechanism can be found in its user and maintenance manual

5、 Principle of Action
The opening and closing actions of this series of isolating switches are basically the same. When linking, the single pole isolation switch needs to be connected separately according to installation diagram 8 or diagram 9.
1. Operating principle of isolation switch
(1) Without grounding switch type
The operating mechanism of the isolation switch is connected to the active stage of the isolation switch through a connecting tube. The main shaft of the mechanism rotates 90 degrees, which drives the insulation support of the active stage to rotate 90 degrees. At the same time, the connecting rod drives the insulation support on the other side to rotate in the opposite direction, achieving the opening and closing action. With the help of the connecting rod, each single pole switch can be connected into a bipolar or three pole linkage isolation switch. It is usually manufactured as a single pole and used as a single pole.
(2) One time operation type with grounding switch blade
The structure of the grounded knife switch is based on the above switch structure, with an additional operation of the grounding transmission mechanism It ensures that when the main switch starts to open, the grounding switch starts to rotate accordingly; When the main switch is turned to the disconnection terminal position, the grounding switch also reaches the grounding terminal position at the same time The opening and closing actions of the main switch and the grounding switch are completed in one go
(3) Secondary operation type with grounding switch blade
This structure uses two handles to operate the main blade and the grounding switch blade respectively A interlocking device is installed between the two operating handles to prevent accidental operation and ensure that the operation is carried out according to the prescribed procedure (main opening ground closing ground opening main closing).
2. Working principle of grounding switch
The handle of the operating mechanism rotates horizontally by 90 degrees, and the grounding switch is driven to rotate through the connecting rod to achieve the opening and closing actions of the grounding switch.
3. The auxiliary switch in the operating mechanism is connected to the main shaft of the mechanism, and when the opening and closing actions are performed, the corresponding contacts are cut off or closed, and corresponding opening and closing signals are issued.

6、 Installation and adjustment
1. The installation and adjustment of isolation switches should meet the following requirements:
(1) When equipped with a manual mechanism, operators with general physical strength should be able to independently perform opening and closing operations with flexible movements.
(2) The closing synchronicity value of the bipolar or three pole linkage of the isolation switch is not greater than 6mm;.
(3) The resistance of each phase circuit of the isolation switch should meet the requirements in Table 3

2. Installation and adjustment of isolation switch
(1) Fix each pole isolation switch base on a horizontal foundation according to installation diagram 8 or 9,
(2) Place the operating mechanism under the rotating spindle on the active side of the isolation switch. When the main body of the isolation switch and the operating spindle of the mechanism isolation switch are in the closed position, use a toothed clamp to connect and tighten the water and gas pipe. When the main and driven insulation pillars are not synchronized, adjust the positive and negative teeth screws between the poles to achieve opening and closing.
(3) The installation and adjustment of the bipolar or interlocking closing synchronization of the isolation switch, under the condition that the two terminals bear normal busbar tension, adjust the length of the positive and negative tooth connecting rods between the phases to meet the above requirements.
(4) When the isolation switch is in the closed position, all contact points on the contacts should be in contact. The tightening degree of the M8 screw on the contacts should be the best state when the spring washer is just flattened and the contact fingers can swing.
3. Installation and adjustment of grounding switch with secondary operation type
(1) When both the grounding switch and the main shaft of the mechanism are in the closed position, use a toothed clamp to connect and tighten the water and gas pipe.
(2) When the grounding switch is in the closed position, the contact position of the contact can be adjusted by placing the grounding contact on the conductive tube. When the closed position is correct, tighten the fastening nut.
7、 Acceptance and storage
1. After the product arrives at the destination, the user should place it in a dry and ventilated place, not invert it, and conduct acceptance as soon as possible according to the following items:
(1) Firstly, check the outer surface of the packaging box for any damage or abnormalities. After the external inspection is completed, open the packaging box and take out the attached documents.
(2) Check whether the documents attached to the product are complete (including packing list, product certificate, installation and use instructions, etc.)
(3) Remove the product and accessories (be careful not to damage the insulation pillar porcelain bottle), and verify.
(4) Check the appearance of the product for any damage or abnormal phenomena.
2. After receiving the product experience, regardless of whether it is installed and used immediately, the following items should be stored and kept:
(1) The friction rotating parts of the isolation switch must be wiped clean and coated with acid free Vaseline for protection.
(2) When products are stored in the warehouse for a long time, they should be inspected regularly (no more than six months each time). If rust is found, the rust layer should be removed and rust inhibitor should be applied.
8、 Instructions for use
1. Before putting into operation, a comprehensive inspection should be conducted to confirm that there are no errors before putting it into operation.
(1) Whether the dimensions of each part of the isolation switch meet the requirements.
(2) The bolts of each connecting part should be securely fastened, especially the connection with the busbar.
(3) All contact points on the contact should be in full contact
(4) After being put into operation, the following matters should be noted:
(5) In general, isolation switches must be opened and closed only after the line load is cut off.
(6) The isolation switch with a secondary operation type grounding switch must be fully opened before the grounding switch can be closed; On the contrary, the closing operation of the isolation switch can only be carried out after the grounding switch is completely opened.
2. Isolation switches must be regularly maintained and inspected, and the following precautions should be taken during maintenance:
(1) Check if the isolation switch porcelain bottle is damaged and if the adhesive is loose.
(2) Whether the contact points on the contacts are in good contact when the isolation switch is in the closed position; Check if the spring on the contact is deformed, if the tension has changed, and measure the circuit resistance.
(3) Whether the auxiliary switches and other components in the organization are well insulated.
(4) Is the grounding condition good.
(5) Whether the rotating parts are flexible during operation and there should be no jamming phenomenon.