5 Must-Have Features in a MNS Low-voltage switchgear

Switchgear forms an integral core in all electrical systems, having controlling, protective, and isolating functions on electrical equipment. Be it industrial, power plant, or even residential, switchgear makes sure that electrical systems run safely and efficiently. But what is switchgear, really, and how does it differ in terms of high, medium, and low voltage switchgear? The blog serves to give information on switchgear, explain all the voltage options that come with it, and how one can select the proper form of switchgear for particular needs.

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What is Switchgear?

Definition and Purpose

All forms of electrical apparatus used for switching, controlling, protection, and isolation of electrical power systems are covered under the term ‘switchgear’ with circuit breakers, switches, fuses, relays, etc. Essentially, switchgear is a way of breaking an electrical circuit in case of a fault like a surge or overload in power, saving the system from damage.
Basically, the switchgear works on three principal considerations: electrical protection, electrical isolation, and control. The systems have, therefore, been designed with aspects of not causing damage to electrical equipment, very commonly isolating circuits in case the system experiences a fault. For example, in case there is an overvoltage, the switchgear automatically disconnects the power supply before overheating, probably causing potential damage, or even fires. Furthermore, switchgear provides safe means to test, maintain, and clear faults of electrical systems as it de-energizes the necessary equipment.

Elements of Switchgear

Switchgear consists of many components all working together to isolate power and protect equipment that it supplies from electrical overloads. These include:

• Fuses: This component protects a circuit by breaking the connection in the event of overload.
• Switches: These either manually or automatically open or close electrical circuits.
• Relays: The detection of faults triggers the necessary action; for example, opening a circuit breaker.
• Isolators: These ensure that it is safe to isolate equipment from the supply of power.
• Circuit Breakers: The circuit shall automatically disconnect in case the fault is detected. Lightning Arresters: To avoid voltage spikes at devices in case of a lightning stroke.

Switchgear Types: LV, MV, and High Voltage Switchgear

Basically, switchgear can be divided into three broad categories: Low Voltage, Medium Voltage, and High Voltage. The division takes into consideration the levels of voltage they deal with. Each category of switchgear caters to different applications and different environments.

Low Voltage Switchgear

• Overview: Low Voltage Switchgear is applied in systems whose voltage does not exceed 1kV. It is commonly found on the low voltage side of the power distribution transformers and is applied in a very expansive range of industries.
• Applications: LV switchgear finds application in residential buildings, small commercial buildings, and industrial facilities. It governs low-voltage services and technology; hence, it’s safe for use by unskilled or non-specialized personnel.

Components and Features

• Main LV Switchboard: When fed by a mains transformer, this would be the largest transformer for a 400V AF Switchgear board at up to 4MVA.
• Sub-Distribution Panels: These are used to get the power closer to the point of application.
• Circuit Breakers: Protect circuits against overload and short circuits.
• Isolators and Switches: Permit safe maintenance/operation.
• Advantages: LV switchgear is relatively straightforward to install and maintain, making it a cost-effective solution for lower power applications.

Medium Voltage Switchgear

• Overview: Medium voltage switchgear shall be intended for systems of 1kV to 35kV. Applied mainly in transmission and distribution systems and also in large industrial plants.
• Applications: Power transmission and distribution lines, generator systems, feeder circuits, and motors in the industrial plants.

Components and features

• Circuit Breakers: A circuit breaker designed to interrupt high current in the event of fault.
• Disconnection/Isolation: This disconnects a part of the circuit for maintenance.
• Protective Relay: This detects a fault and trips the circuit to prevent damage.
• Gas-insulated Switchgear: The use of its gas sulfur hexafluoride is the medium for insulation; basically, its insulating properties are so good that it occupies less space.
• Benefits: The price-sized-performance balance of MV switchgear is relatively excellent, thereby making it well-suited for very broad spectrums of industrial and utility applications.

High Voltage Switchgear

• Overview: High Voltage Switchgear operate at above 35kVs of voltage and find their applications in large power systems like transmission networks and substations. Major insulation and arc-quenching ability is required due to high voltage systems.
• Applications: High Voltage Switchgear finds application mainly in generation and transmission systems of power, including substations and power plants.

Components and their features

• Circuit Breakers: The circuit breakers have to be highly reliable since they deal with High Voltage Switchgear and current levels.
• Gas Insulated Switch Gear (GIS): Compact and hence used in High Voltage Switchgear due to its better insulation properties.
• Arcing Protection: Special Design and materials are used to control that enormous energy evolved during breaking.

Types of High Voltage Switchgear

• Minimum Oil Circuit Breakers (MOCB): Uses minimal quantity of oil for arc quenching.
• Air Blast Circuit Breakers: Uses high pressure air for arc extinction.
• SF6 Circuit Breakers: These are the circuit breakers in which sulfur hexafluoride gas is used and is best in arc quenching and insulation.

Advantages: The High Voltage Switchgear ensures safe control and qualifies large power systems with features that control high energy and voltage levels.

How to Choose the Right Switchgear

The criteria to the right type of switchgear selection would be related to voltage level, application requirements, and safety and reliability.

Consider the Following at the Time of Choosing Switchgear:

• Voltage Requirements: The system voltage level should be defined at either LV, MV, or High Voltage Switchgear to define the type used for switchgear.
• Power Load: Be aware of how much power your system is going to draw to ensure that switchgear can handle the load.
• Environmental Conditions: The installation environment—indoor, outdoor, or harsh conditions—is the second parameter that one must consider in choosing the correct type of switchgear.
• Safety Standards: Ensure that all relevant safety standards and certifications concerning the switchgear are compiled.
• Maintenance Needs: The ease of maintenance of the switchgear, and the availability of the service facilities for it.

Frequently Asked Questions (FAQ)

What are the basic functions of switchgear?

Switchgear can provide control, protection and conduct the isolation of electrical systems to make sure that operations are carried out in a safe and reliable way.

How is switchgear different according to the type of voltage?

The main difference comes in the level of voltage each is capable of: LV is up to 1kV, MV from 1kV to 35kV, and HV above 35kV. All of them have their fields of utilization, regarding requested power and system specifications.

With competitive price and timely delivery, AOKEYER sincerely hope to be your supplier and partner.

Can Low Voltage switchgear be used in industrial settings?

Yes, it is used in the small industrial set-ups, and even the voltage here does not go above 1kV. However, in large industry applications, MV or HV switchgear may be needed.

What are the safety features used in High Voltage Switchgear?

The HV switchgear has developed safety features such as arc-quenching mechanisms, insulation using gases, and the use of beefy circuit breakers to be able to manage high energy levels without any incidents.

How often is the switchgear maintained?

Switchgear shall be maintained at periodic intervals for safe operation. This shall be performed, at maximum, every 12 months, or at such time as recommended by the manufacturer by inspection, cleaning, and making the necessary tests.

Conclusion

Understanding the differences between low, medium, and high voltage switchgear is imperative toward making a characterization that fits your needs. The choice of proper switchgear, be it in household, commercial, or even industrial electrical systems, is tantamount to ensuring the safety and reliable running of the system. And you will make effective decisions by considering voltage requirements, power load, and environmental conditions.

Getting the right switchgear is not about meeting some immediate need for power; it’s all about the long-term safety and efficiency of electrical systems. With the right information from this guide, you will be better equipped to choose switchgear that protects your infrastructure and keeps operations running smoothly.

Product description

The MNS type low-voltage withdrawable switchgear (hereinafter referred to as the switchgear) is developed by our company after referring to the Swiss ABB company’s MNS series of low-voltage switchgear and comprehensively improving it. It is currently the most advanced low-voltage withdrawable switchgear in China. This product is composed of standardized and series modules, and the drawer has a reliable mechanical interlocking device, which makes the user safer and more reliable when using it.
This switchgear is suitable for three-phase five-wire power supply systems with AC 50 (60) Hz, rated insulation voltage and working voltage of 380 (400) V, 660V, and rated current of A and below. It can be used in power plants, substations, Industrial and mining enterprises, buildings, hotels, airports, docks, radio and television and other communication centers are used to control power generation, transmission and distribution, power conversion, and power consumption equipment, and use capacitor compensation cabinets to compensate for their main bus reactive power.

The latest features of advanced MNS

1. On the upper ventilation door, cable room door and back door, the rotating part is changed from concealed hinge to open hinge, which makes the door rotate smoothly, the angle of rotation is larger, and it is more beautiful than before, and the overall effect is more coordinated.
2. Before the improvement, the primary adapter is directly connected with the plastic functional part. If a special failure occurs, which causes the adapter to burn out, it will bring greater difficulties to on-site maintenance and longer replacement time. After the improvement, because the one-time adapter is changed to independent installation and maintenance, it reduces the power outage time and has significant economic benefits.
3. The primary cable outlet mode of the MCC cabinet is more flexible. Compared with the previous, in addition to retaining the original sideout and back-out solutions, it also adds a simultaneous side-out and back-out hybrid solution, which greatly facilitates users.
The specifications of the primary cables in the drawers of 4.8E, 16E and 24E units can be selected according to the actual current size of the loop, which is conducive to the maintenance and modification of the user on-site.
5. After the improvement, the rear door structure of the rear outlet scheme is compared with the previous one, and the center column has been re-optimized, thereby increasing the space for the outlet cable and facilitating user maintenance. At the same time, the operation is more convenient and simple, and has the independent characteristics of permanent products.
6. After the improvement, the secondary connector of the rear outlet scheme is changed from the side position to the rear partition position.
In this way, not only the distance between the secondary cable and the terminal is reduced, but also the problem that the on-site cabinets cannot be overhauled after the cabinets are combined is avoided. (After 600mm wide, the outlet plan is easy to produce)

Conditions of Use

1. The ambient air temperature is not higher than +40°C, not lower than -5°C, and its average temperature within 24h is not higher than +35°C.
2. The relative humidity of the surrounding air does not exceed 50% when the highest temperature is +40°C, and there is a larger relative humidity at a lower temperature, such as 90% at +20°C, but considering the temperature changes May occasionally produce moderate condensation.
3. For indoor use, the altitude of the place of use shall not exceed m.
4. It should be installed in a place where there is no severe vibration and impact, and the electrical components are not corroded.

Want more information on MNS Low-voltage switchgear? Feel free to contact us.