Product Overview
The GCS low-voltage withdrawable switchgear is suitable for the distribution systems of power plants, petroleum, chemical, metallurgical, textile and high-rise building industries. In large power plants, petrochemical systems and other places with a high degree of automation and a requirement for computer interfacing, it serves as a low-voltage complete distribution device for power distribution, centralised motor control and reactive power compensation in generation and supply systems with three-phase AC frequency of 50 (60) Hz, rated operational voltage of 400 V and 660 V and rated current of 5000 A and below.
The design of the assembly complies with the following standards: IEC439-1 Low-voltage switchgear and controlgear assemblies; GB7251 Low-voltage switchgear assemblies.
Type Designation
Service Conditions
- The ambient air temperature is not higher than +40 ℃ and not lower than -5 ℃, and the average temperature within 24 h shall not be higher than +35 ℃. If exceeded, derating operation shall be applied according to the actual conditions;
- For indoor use, the altitude of the installation site shall not exceed 2000 m;
- The relative humidity of the ambient air does not exceed 50% at the maximum temperature of +40 ℃; a higher relative humidity is permitted at lower temperatures, for example 90% at +20 ℃, and the possible effect of occasional condensation due to temperature changes shall be taken into account;
- The inclination of the assembly to the vertical plane during installation does not exceed 5°, and the whole row of cubicles is relatively level (in accordance with GBJ232-82);
- The assembly shall be installed in a place free from violent vibration and shock and where the electrical components will not be subject to undue corrosion;
- Where the user has special requirements, these can be resolved through consultation with the manufacturer.
Main Technical Parameters
The basic technical parameters are given in Table 1.
| No. | Name | Value | |
|---|---|---|---|
| 1 | Rated voltage of main circuit (V) | AC 400/660 | |
| 2 | Rated voltage of auxiliary circuit | AC 220, 380 (400); DC 110, 220 | |
| 3 | Rated frequency (Hz) | 50(60) | |
| 4 | Rated insulation voltage (V) | 660 | |
| 5 | Rated current (A) | Horizontal busbar | ≤5000 |
| 6 | Vertical busbar (MCC) | 1000 | |
| 7 | Rated short-time withstand current of busbar (kA/1 s) | 50，80 | |
| 8 | Rated peak withstand current of busbar (kA/0.1 s) | 105，176 | |
| 9 | Power-frequency test voltage (V/1 min) | Main circuit | 2500 |
| Auxiliary circuit | 2000 | ||
| 10 | Busbar | Three-phase four-wire | A.B.C.PEN |
| Three-phase five-wire | A.B.C.PE.N | ||
| Degree of protection | IP30、IP40 | ||
Main Circuit Schemes
The main circuit schemes of the GCS cubicle total 32 groups and 118 specifications, excluding schemes and specifications derived from changes in the control and protection of auxiliary circuits. They cover the needs of power generation, power supply and power consumption as well as other power users; the rated operational current is 5000 A, suitable for distribution transformers of 2500 kVA and below. In addition, a capacitor compensation cubicle is designed to meet the need to improve the power factor of supply and consumption, and a reactor cubicle is designed to meet the need for overall investment.
Auxiliary Circuit Schemes
The GCS auxiliary circuit album contains 120 auxiliary circuit schemes in two volumes: Volume 1, AC Operation, contains 63 schemes and Volume 2, DC Operation, contains 57 schemes.
The auxiliary circuit schemes of the DC operation part are mainly used for the low-voltage station service systems of power plants and substations. They apply to the low-voltage station service systems of units of 200 MW and below and of 300 MW and above, and to the general control modes of the working (standby) source incoming line, source feeders and motor feeders.
The auxiliary schemes of the AC operation part are mainly used for the low-voltage systems of substations in factories, mines and high-rise buildings. There are 6 combined schemes applicable to dual-source operation control. Control circuits for operational electrical interlocking, automatic standby source switching and automatic restoration are also provided, which can be used directly in engineering design.
Where DC is used for the control supply, the voltage is DC 220 V or 110 V; where AC is used, the control supply is AC 380 V or 220 V. The complete cubicle is composed of drawer units. The 220 V control supply is taken from the common control supply provided by a dedicated control transformer in the cubicle; the common control supply uses an unearthed control transformer, and a 24 V supply is reserved for use where weak-current signal lamps are required.
For the installation location of the electricity meters, the method of introducing voltage signals and other installation and operating requirements, see the Compilation Notes of the auxiliary circuit diagrams.
Main Busbar
To improve the dynamic and thermal stability of the busbar and to reduce the temperature rise of contact surfaces, TMY-T2 series hard copper bars are used throughout; the copper bars are tin-plated over their full length, and silver-plated copper busbars over their full length may also be selected.
- The horizontal busbar and vertical busbar are installed separately in the busbar compartments inside the cubicle.
- The neutral earthing busbar is made of hard copper bar, running through as a horizontal combined protective and neutral conductor (PEN) or as separate protective and neutral conductors (PE+N).
Selection of Electrical Components
The GCS cubicle mainly selects electrical components with high and stable technical performance that use imported technology and can already be mass produced domestically.
Main Switch
- For incoming and feeder switches of 630 A and above, the DW45 series is mainly selected; the DW48, AE, 3WE or ME series may also be used, and where deemed necessary the imported M or F series may be used.
- For feeders and motor control switches below 630 A, moulded-case switches of the TG, CM1, NM, CDM and TG30 series are mainly selected.
- To improve the dynamic stability of the main circuit, combined busbar clamps and insulating supports dedicated to the GCS series are designed; they are thermoformed from high-strength flame-retardant synthetic material, with high dielectric strength, good self-extinguishing performance and a unique structure.
- To reduce the temperature rise of the partitions, connectors and cable terminations of the functional units, dedicated adapters for the GCS cubicle are designed; these adapters have a large capacity and reduce the temperature rise.
- If the design department selects new electrical components with better performance and more professional technology according to user needs, the GCS series cubicles have good universality, so updating the components will not cause difficulties in manufacture and installation.
| Dimensions (mm) | |||||
|---|---|---|---|---|---|
| Cubicle height (H) | 2200 | ||||
| Cubicle width (D) | 400 | 600 | 800 | 1000 | - |
| Cubicle depth (W) | 800 1000 | 800 1000 | 600 800 1000 | 600 800 1000 | - |
| No. | Name | Tolerance (mm) |
|---|---|---|
| 1 | Verticality | 3.3 |
| 2 | Levelness | Top of two adjacent cubicles 2 |
| Top of a row of cubicles 5 |
||
| 3 | Unevenness | Sides of two adjacent cubicles 1 |
| Sides of a row of cubicles 5 |
||
| 4 | Gap between cubicles | 2 |
Installation & Operation
After the product arrives at the receiving site, first check whether the packaging is intact; if any problem is found, notify the relevant contract department in time to make a commercial record, jointly analyse the cause and carry out evidence collection and follow-up handling. Products that are not installed immediately shall be placed and kept properly in a suitable location in accordance with the normal service conditions and the temporary storage regulations for electrical equipment.
◆ The product shall be installed according to the installation diagram. The foundation channel steel and the bolts for bolt fixing shall be provided by the user. When connecting the main busbar, if the surface is uneven due to transport or storage, it shall be made flat before connection and tightening.
◆ When the equipment is installed singly or in a row, the deviations in verticality, unevenness of the cubicle faces and gaps between cubicles shall comply with the requirements of Table 3.
Inspection & test before commissioning
- Check whether the paint or other covering material (such as plastic coating) on the cubicle surface is damaged and whether the interior is dry and clean.
- Check whether the operating mechanisms of the electrical components are flexible, without jamming or excessive operating force.
- Check whether the making and breaking of the main apparatus is reliable and accurate.
- Drawers or withdrawable mechanisms shall be pulled out flexibly and lightly, without jamming or collision.
- The centre lines of the moving and fixed contacts of the drawer or withdrawable structure shall be aligned and the contacts shall touch tightly. The insertion depth of the main and auxiliary contacts shall meet the requirements. The mechanical or electrical interlock shall operate correctly and both locking and release shall be reliable.
- Drawers with identical primary schemes, secondary principles and dimensions shall be easily interchangeable, without jamming or collision.
- When replacing fuse links, the engineering design requirements shall be met.
- The protection settings shall be set correctly according to the actual load.
- The insulation resistance measured with a 1000 V megohmmeter shall not be lower than 10 MΩ。
- All busbar connections shall be sound and insulating supports, mounting parts and other accessories shall be installed firmly and reliably.
Precautions for use
- The equipment is a low-voltage distribution cubicle installed away from the wall, operated from the front and maintained from both sides. The maintenance channel and doors of the cubicle may only be entered or opened by qualified professional personnel for operation, inspection and maintenance.
- After many opening and closing operations, especially after short-circuit opening and closing, the contacts of air circuit breakers and moulded-case circuit breakers may be locally burnt and carbon deposits produced, increasing the contact resistance; maintenance and servicing shall be carried out according to the circuit breaker instruction manual.
- After installation and maintenance, the isolation between compartments and between functional units shall be strictly checked to ensure good functional segregation of the assembly and to prevent the expansion of faults.
Drawer operation
- Operation of the 1/2 drawer
The operating mechanism of this drawer consists of the rotating part, the shaft and the latch, and provides the functions of closing/opening, test, isolation and locking of the switch. The operating mechanism is also fitted with a microswitch for electrical interlocking.
Description of Basic Operating Positions
Ⅰ Connected position: the main switch is closed, both the main circuit and the control circuit are connected, and the functional unit is locked.
○ Open position: the main switch is open, the control circuit is connected, and the functional unit is locked.
↷ Test position: the main switch is open, the main circuit is disconnected, the control circuit is connected, and the functional unit is locked.
↶ Isolated position: the drawer is withdrawn by 30 mm; both the main and control circuits are isolated and disconnected, and the drawer is locked.
↕ Withdrawn position: both the main circuit and the control circuit are disconnected, and the drawer can be withdrawn freely.
The operating handle can be turned from the (○) position to the (Ⅰ) position only after being pressed in by 6 mm.
↶ Operating sequence: only in the withdrawn position (↕) can the drawer be pushed in or pulled out; after turning 45° anticlockwise the drawer automatically reaches the isolated position (↶) when pulled out. Turning a further 45° anticlockwise reaches the test position (↷). Then turning 45° clockwise reaches the switch open position (○). The handle is pressed in by 6 mm and turned 90° clockwise to close the switch; to withdraw, the operations are performed in reverse order.
If necessary, a padlock can be added to the operating handle in the three positions of main switch open, test and isolation as a safety safeguard.
Operation of Drawers of 1 Unit and Above
The operating mechanism of this drawer consists of the shaft, a cylindrical cam, clutch plates, a pin compression spring and a shifting fork. Turning the cylindrical cam by the operating handle racks the drawer in and out and simultaneously provides the functions of opening, closing, test, isolation and locking of the switch.
Ⅰ Connected position: the main switch is closed, both the main circuit and the control circuit are connected, and the functional unit is locked.
○ Open position: the main switch is open, the control circuit is connected, and the functional unit is locked.
↷ Test position: the main switch is open, the main circuit is disconnected, the control circuit is connected, and the functional unit is locked.
↶ Isolated position: the drawer is withdrawn by 30 mm; both the main and control circuits are isolated and disconnected, and the drawer is locked.
↕ Withdrawn position: both the main circuit and the control circuit are disconnected, and the drawer can be withdrawn freely.
The operating handle can be turned from the (○) position to the (Ⅰ) position only after being pressed in by 9 mm.
↶ Operating sequence: only in the withdrawn position (↕) can the drawer be screwed in or out; turning the operating handle 30° clockwise reaches the isolated position (↶), then 180° further clockwise reaches the test position (↷), then a further 30° clockwise reaches the switch open position (○); the handle is pressed in by 9 mm and turned 90° clockwise to close the main switch. To withdraw, the operations are performed in reverse order.
If necessary, a padlock can be added to the operating handle in the three positions of main switch open, test and isolation as a safety safeguard.
Unlocking Mechanism
There is a red plastic button at the lower right corner of drawers of 1 unit and above; this is the unlocking mechanism. When the operating mechanism is faulty, maintenance is required or the door needs to be opened, with the operating handle in the “○” position the red plastic button is pressed downwards to open the door.
Outline & Installation Dimensions
(mm)
| Cubicle width (D) | Cubicle depth (W) | Cubicle height (H) |
|---|---|---|
| 600，800，1000 | 800，1000 | 2200 |
Delivery Documents & Accessories
◆ The manufacturer shall supply the following documents and accessories
- ◇ Packing list
- ◇ Product certificate and factory test report
- ◇ Instruction manual
- ◇ Relevant electrical drawings
- ◇ Instruction manuals of the main components
- ◇ Cubicle door keys, operating handles and spare parts specified in the contract
Ordering Information
◆ The user shall provide the following when ordering:
- ◇ Main circuit distribution system diagram and layout drawing, rated operational voltage, rated operational current, setting current of the protection device and the necessary technical parameters.
- ◇ Specify the specifications of the incoming and outgoing cables.
- ◇ Models, specifications and quantities of the main electrical components in the switchgear.
- ◇ If a busbar bridge or busway is required between switchgear cubicles or for the incoming cubicle, the specific data such as span and height above ground shall be stated.
- ◇ If the switchgear is used under special environmental conditions, this shall be described in detail when ordering.
- ◇ Surface colour of the switchgear and other specific requirements.
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