Performance Indicators
The design of the equipment complies with the following standards:
IEC 439-1 Low-voltage switchgear and controlgear assemblies
GB 7251 Low-voltage switchgear and controlgear assemblies
ZBK36001 Low-voltage withdrawable complete switchgear
Main Structure
1. The main frame is constructed using 8MF open-section steel, with both sides of the profile featuring mounting holes with moduli of 20mm, 100mm, and 9.2mm, allowing for flexible and convenient internal installation.
2. The main frame assembly is designed in two forms: a fully assembled structure and a partially welded structure (side frames and crossbeams), for user selection.
3. The functional compartments of the equipment are isolated from each other, divided into the functional unit compartment, busbar compartment, and cable compartment. Each compartment operates relatively independently.
4. The horizontal main busbars are arranged in a flat, rear-mounted configuration to enhance their ability to withstand electrodynamic forces, constituting a fundamental measure to ensure the equipment's main circuit possesses high short-circuit withstand capability.
5. The design of the cable compartment facilitates convenient cable entry and exit from both the top and bottom.
Functional Units
1. The modular height for drawers is 160mm. Drawers are divided into five size series: 1/2 unit, 1 unit, 3/2 units, 2 units, and 3 units. The rated current for unit circuits is up to 400A.
2. Drawer variations occur only in height dimensions; width and depth remain constant. Drawers of identical function feature good interchangeability.
3. A single MCC cabinet can accommodate a maximum of 11 one-unit drawers or 22 half-unit drawers. Drawers larger than one unit employ a multi-functional rear panel.
4. Drawer power connections use plug-in components of the same specification with varying numbers of contact plates, depending on the current rating.
5. The connection between half-unit drawers and the cable compartment utilizes a backplate-style ZJ-2 type adapter.
6. The connection between full-unit drawers and the cable compartment uses rod or tube structure ZJ-1 type adapters of the same size, categorized by current rating.
7. Drawer units are equipped with mechanical interlocking devices.
Main Electrical Components
The selection principle for main electrical components is based on imported technology, domestic capability for series batch production, and meeting the equipment's high-performance requirements.
1. Circuit breakers for power supply and feeder units primarily select the AH series. Alternatively, more advanced series such as Schneider's M series or ABB's F series can be chosen. The AH type circuit breaker features good performance, compact structure, relatively light weight, strong series compatibility, relatively lower price, convenient maintenance and operation, and its performance indicators meet the requirements of this equipment.
2. Circuit breakers for drawer units (motor control units, some feeder units) primarily select CM1, TG, and TM30 series molded case circuit breakers, with some selecting the NZM-100A series produced by MOELLER. These switches feature good performance, compact structure, short or no arcing, and high technical-economic indicators, satisfying the requirements of this equipment.
3. Disconnectors and fuse-disconnectors select the Q series. This series offers high reliability, strong breaking capacity, and allows for mechanical interlocking.
4. Fuses primarily select the NT series.
5. AC contactors select the B series and LC1-D series.
Equipment Characteristics
1. Increased thermal capacity of adapters significantly reduces the additional temperature rise imposed on connectors, cable terminations, and partition boards due to adapter heating.
2. Clear and reliable separation between functional units and compartments ensures that a fault in one unit does not affect others, limiting faults to the smallest possible scope.
3. The flat arrangement of busbars provides good dynamic and thermal stability, enabling the equipment to withstand short-circuit current impacts of 80/176kA.
4. The number of circuits in a single MCC cabinet can be as high as 22, adequately addressing the needs of automated valve/actuator groups in industries such as large single-unit capacity power generation and petrochemical systems.
5. Connection to external cables is completed within the cable compartment, allowing cables to enter/exit from top or bottom. Current transformers are installed in the cable compartment, facilitating convenient installation and maintenance.
6. For a given power distribution system, current-limiting reactors can be matched to limit short-circuit current, stabilize busbar voltage within a certain range, and partially reduce requirements for component short-circuit withstand capability.
7. Drawer units are equipped with a sufficient number of secondary connectors (32 pairs for 1-unit and above, 20 pairs for 1/2 unit), meeting the contact point requirements for computer interfaces and automatic control circuits.
