Professional Manufacturer Of RMU Switchgear from China

KDM RMU Switchgear

Mainly, KDM leading manufacturer located in China. Our RMU Switchgear designed for underground cable supply. KDM fabricated RMU switchgear suited in many applications such as compact secondary substations and many more. This is a factory assembled, uses in load connection points of any distribution networks. KDM RMU switchgear is designed for a ring power supply networks. By that, it can feed from second failure of first source of supply.

We, KDM, have our watchful and professional staff of the engineering team to support and meet your need in providing your special requirements.  In over 10 years of fabricating such products, we trained well our employees on how they manage and develop our way of services. With our eco-friendly staff, our customers will not be hesitated in dealing with us.

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KDM RMU switchgear or ring main unit switchgear can be suited in solar and wind power plants including small industries. Most of the hotel owners or buildings choose to use these types of power to supply. Our team makes RMU or ring main unit switchgear easy to operate. With durable switchgear for ring main units, it is innovative solutions to help operators manage many challenges easily. KDM fabricated RMU switchgear for safety performance. If you want your own design, you can deal with one of our engineering experts so they can meet what you wished for your RMU switchgear.

We, KDM develop our creativeness in fabricating products of RMU switchgear and many others related in electrical enclosures. Currently, we used high-tech machines for durability and the best quality of RMU switchgear. There are many choices in purchasing RMU switchgear. Each designs, features, customization and functions has its own rates. We assuring that each functions and application will suit enough for your needs.

KDM is very dedicated on their responsibilities. If we’re talking about engineering, manufacturing standard products, we, KDM has our team who did their best to provide all of satisfying service you need. We are doing our best to provide quick actions by the help of our well-oriented teams. Our perfect packaging for every order is flexibly provided. KDM is perfect for those who urgently need to order electrical enclosure such RMU switchgear. We only focus on manufacturing on it so we can also focus our attention on your ordered products. We, KDM are one stop solutions for electrical needs of every business people.

The best solutions for enclosure can be provided if you choose to deal with one of our professional staff assigned. If you have courage on doing that, being a successful is possible for you. Contact directly us now and let us help you grow your business. Keep in touch!

Ring Main Unit (RMU) Switchgear: The FAQ Guide

Before investing in a new RMU switchgear, you should read this guide.

It covers the fundamental working specifications and parameters of the ring main unit switchgear.

Through this guide, you will get more insights and be an expert in these switchgear components.

What is a Ring Main Unit (RMU) Switchgear?

A Ring Main Unit (RMU) Switchgear is a kind of switchgear that has anSF6gas-insulated compact unit and fully sealed.

The Ring Main Unit (RMU) Switchgear is compacted and sealed with metal enclosure for life.

They come in a range of design, voltage rating, and configurations.

 Ring main unit switchgear

What is the function of Ring Main Unit Switchgear?

The Ring Main Unit (RMU) is an enclosed, sealed, and compact kind of switchgear that is fundamentally used for average voltage power supply.

Generally, it is like a complete switchgear.

It is composed of the basic apparatus like protection gadgets, metering gadgets, and switching devices.

The Ring Main Unit (RMU) switchgear equally plays an important role in the secondary energy supply system.

The vital functions of Ring Main Unit (RMU) switchgear are:

a) Protection

It protects the electrical circuit from the defective short-circuiting currents, faulty earth currents, and overload.

b) Isolation

It detaches the damaged electrical gear from the remaining electrical circuit

c) Management of Circuits

It helps in controlling the circuit for efficient switching.

What are the Advantages of Ring Main Unit (RMU) Switchgear?

Some of the main benefits of RMU switchgear include:

• Compact Design

Ring Main Unit Switchgear has insulation of an SF6.

The system features a vacuum circuit disconnect and SF6 Switch breaker.

Its design of compactness needs minimum probable space to install and manage.

• Smart Capabilities

The RMU switchgear is simple to incorporate with the management energy supply system and in the construction of an intelligent grid resolution.

It is always a guarantee since it comes with smart electronic gadgets and better technological advancements.

• Cost and Time Averting

The Ring Main Unit (RMU) Switchgear is a comprehensive electronic disconnect.

It protects the systems. The installation is simple and not need many requirements.

Besides, conserving installation and authorizing time.

You can adapt it to most environmental conditions.

• Performance & Safety

The newest technological advancement and latest design, compactness of Ring Main Unit (RMU) switchgear largely contribute towards ensuring comprehensive safety.

It makes it dependable and effective.

What are the Disadvantages of Ring Main Unit (RMU) Switchgear?

Some of the main challenges of using RMU switchgear are:

 RMU Switchgear

Using Sulphur hexafluoride () Gas

The Sulphur hexafluoride () gas was common in both high voltage switchgear and low voltage switchgear for quite some time.

Although it is popular due to its desirable properties, the gas has some negative effects on the environment.

Therefore, those who are environmentally conscious will try to avoid it.

Today, most people are going for for vacuum insulation instead of Sulphur.

Of course, Sulphur hexafluoride () gas is also popular due to better interrupting and insulation properties due to excellent quenching capability and dielectric strength.

 SF6

For safety purposes, you should consider the following when dealing with RMU switchgear:

The handling Sulphur hexafluoride () gas, can encompass several circumstances during:

• Maintenance operations
• Refilling of switchgear
• Discharging of Sulphur hexafluoride () gas-filled gear
• Reutilizing of used gas

In all these circumstances, you should have appropriate protective safety gear like oxygen detectors, respirators, and so on.

In the case of negligence, catastrophic incidences may occur. The Sulphur hexafluoride () gas has a density surpassing that of air five times.

Hence, if released into the environment, the gas tends to accrue originally in low-lying places, where natural ventilation does not exist.

This can result in suffocation, thus casualty.

Alternative to Sulphur hexafluoride () gas

The use of a vacuum can be a suitable alternative.

For economic purposes and safety from arc flash, Sulphur hexafluoride () gas is still highly rated to be the best.

Which Components make Ring Main Unit Switchgear?

Some of the main components of RMU switchgear include:

Parts of RMU Unit

· Remote Terminal Unit (RTU)

When the Ring Main Unit (RMU) switchgear comes with Remote Terminal Unit.

It has a special function in the switchgear since it allows for the implementation of intelligent applications.

The intelligent application is to connect the Ring Main Unit (RMU) Switchgear with the communication network.

This enables surveillance and control of the switchgear distantly.

The Terminal Remote Unit (RTU) gathers data from the sensors and field instruments.

It then conveys the information to the Regulatory Control & Data Attainment System.

You can install this in the central regulator point via lines & communication systems.

Then, it obtains control instructions from the tele-meter and tele-control system to direct online regulations in actual time.

· Load Break Switches

The LBS is a switch you can use to shift medium voltages from 1000 Volts to 33 kV.

It is a kind of standby for the two-pole structure.

It offers protection to the Ring Main Unit switchgear and transformer.

The load brake switch has several features that contribute to its efficiency.

Some features are standard; implying, they should not miss in the system.

There are also optional features, which the system can work without.

According to the IEC 62271 ratings for this Load Break Switch (LBS), the ratings range from 12 kV to 24 kV.

Some of the standard features are:

• Three-point load break switches compost of earthing and disconnector switch.
• An operational mechanism consisting of; two distinct shafts for earthing and load purpose.
• Cable bushing flat in front comprising of a unified capacitor for voltage signaling
• Switch point signal for ES & LBS.

The optional features can be:

• Motor action ofa switch for load break.
• Voltage indicating system
• Auxiliary switches, they comprise of earthing switch location, & point switch for load break.
• Earth fault and short circuit pointer

Advantages of Load break switch include:

i. It is cheaper compared to a two-pole structure

ii. Safer since it offers protection from faults

iii. Simple to switch the source

iv. Requires minimal space

All these make it suitable for RMU switchgear since it comes as a closed unit.

The load break switchgear may also come with:

• Heaters, which assist in keeping the internal temperature to be constant
• Earth switches with interlocks, which provide extra safety to operators.
• Spring charge pointer.

· Circuit Breaker

The ratings should be of that of the IEC ratings. Its ratings range from 12 kV to 24 kV.

Some of the features of a circuit breakerare:

Circuit breaker

• Vacuum circuit breaker rated at 630 A for protecting feeder or vacuum circuit breaker rated at 200 A for protecting the transformer.
• Three locationsearthing and disconnecting switch
• Cable bushing horizontally in front.
• Switch position pointer for DS/ES & CB.
• Interlocking amid DS/ES & CB.
• Motor action for circuit breaking.
• Tripping coil and closing coil- it is a regulating gadget which trips the circuit breaker from a distant point when applying voltage constantly across 200ms to coil stations.
• Auxiliary switches which include CB location and disconnector location
• Voltage pointer system.

· Vacuum Interrupter

The working mechanism of Vacuum interrupter

In the closed position, typical current flows via the interrupter.

When a defect arises, and interruption is needed, the connections split instantly.

The arc derived amid the surfaces of a link is swiftly shifted across the fitted interaction surface by self-induced magnetic impacts.

As a result,it blocks the overall contact destruction and the creation of a high thermal section on the surface.

Normally, the arc blazes in an ionized metal mist, which reduces the effect of a metal shield.

At zero current, it extinguishes the arc, and the production of vapour terminates.

Then there will be rapid metal vapour plasma dispersion.

Again, cooling, recombination, and deionization of metal vapor plasma.

Conclusively, the metal vapor products consolidate rapidly so that the connections tolerate the transient recuperation voltage.

· Combination of Switch & Fuse

This involves:

• Three locations of a combination of switch and fuse with earthing switch.
• Switch location pointer for a combination of switch & fuse and earth switch
• Fuse bearer for DIN type for connections of fuse
• Cable bushing horizontally in front
• Fuse-connecting rating, which is: 24 kV: max: 75 A, LSIS DIN of fuse-connect type, 12/17.5 kV: max. 100 A, LSIS DIN of fuse-connect type.
• Trips automatically to safeguard from defective current when a fuse burns out

Other features are:

• Motor operational for fuse and switch linkage.
• Auxiliary switches: fuse puffed status & LBS location.

The auxiliary switch is a link you can use to monitor the ON/OFF location of load breaking switch/ fuse merger switch from distant places.

• Tripping coil.
• Voltage pointing system.
• Power Fuse

Also, this is another important component of the Ring Main Unit switchgear.

Characteristics

• The power fuses disrupt high currents before the greatest value. Consequently, reducing the required resist capacity of the related device on the electric power system.
• Although it is small, it owes a high interrupting capacity, and its covered type is appropriate for utilization within the panel board.
• Normally, you can fit the fuses with striking pins for tripping pointers as well as for imposing inclination to trip linkage of associated load switches.

· Current Relay (OCR): Current Transformer (CT) Motorized Safeguard Relay

This type of relay is a self-motorized relay by the Current Transformer (CT) in Ring Main Unit (RMU) switchgear.

You can set it to a fixed time and inverted time features for short circuit, defective earth current, and overload current.

The relay is likewise supplied with a digital recollection for storing the latest tripping values.

This kind of relay has demonstrated to be dependable, and it is an extensively recognized method of safety in the global power distribution networks.

· Voltage Pointer Lamps (Voltage Detector)

It is a device for checking the existence or deficiency of voltage in the cables.

It conforms to the standards of the IEC 61958.

You can get push-button with an LED voltage pointer.  Also, it delivers the power lamp by bushing type capability partitions.

How does RMU Switchgear compare to Extensible Switchgear?

The extensible switchgear is composed of two defect-make load breaking ring switches and a tee-off vacuum breaking circuit.

They are all contained within a common point – the SF6 gas insulating stainless enclosure.

Although, the extensible switchgear does not have the remote terminal unit while RMU switchgear comes with the RTU.

Besides, you can operate the extensible switchgear manually while the RMU Switchgear being an automatic system.

How do you Test Ring Main Unit (RMU) Switchgear?

Testing RMU switchgear ensures it conforms to the set quality standards.

You can test and check the following:

• Rigidity check to avoid any leakage since SF6 gas is toxic
• Checking on the Filling pressure
• Measurement of opening and closing velocity
• Preferential discharge check
• Dielectric test
• Functional torque measurement
• Compliance with the diagrams and drawings.

What is RMU Switchgear Specification?

When shopping for RMU switchgear, you should consider the following parameters:

i. Design Specification of RMU Switchgear

a) Capability to function even in adverse or severe environmental circumstances.

b) Reasonable insulation property

c) Convenience, life span, and maintainability

d) Resistance to disturbance and electrical stress

e) conventional surge containment characteristics

ii. Capability to Function in Adverse Environment

The system should be resistant to corrosion; hence, the enclosure should be steel metal clad.

Again, it should work in the outdoor and resistant to severe weather conditions.

iii. Reasonable Insulation Property

Insulation must conform to the IEC standards. This should cover both performance and safety.

iv. Convenience, Life Span and Maintainability

The Ring Main Unit switchgear should be one that is convenient, with a minimal maintenance cost and a longer life span of about 15 years.

This makes it economical and stress-free.

v. Resistance to Disturbance and Electrical Stress

The electronic and electrical components of RMU switchgear should conform to IEC regulations and standards.

Besides, it should be resistant to electrostatic discharge, radiation disturbance, or electromagnetic interference.

vi. Conventional Surge Containment Characteristics

The design of RMU should be able to endure voltage surge and safeguarded against part failure that can be caused by instantaneous voltage supply.

What are the Common Faults in RMU Switchgear?

Many RMU switchgear systems come as medium voltage switchgear.

In most cases, you will experience faults in the bus bars, jumper cables, and cable terminals.

Normally, the faults are due to defective connections.

This may lead to an increase in resistance, which can result in overheating.

In most cases, overheating will cause thermal failure.

Does RMU Switchgears have Safety Features?

The SF6 gasused in RMU switchgear safeguards the system from arc flash.

Again, the load break switchin the RMU offers its protection in case of faults like short-circuiting, withdrawal of overvoltage and so on.

What are Ring Main Unit Switchgear Quality Standards?

Like other electronic components, RMU switchgear should be CE, IP rated, IEC, EMC, CCC, and UL compliant.

Remember, the quality compliance requirements will depend on where you intend to use the RMU switchgear.

Does RMU Switchgear have Backup Protection?

Yes.

Depending on the design of the RMU switchgear, they have circuit breakers, fuses, or switch disconnectors, alongside other control mechanisms.

Can you Experience Arc Flash on RMU Switchgear?

Ring Main Unit Switchgear does not experience arc flash.

Therefore, this characteristic makes it safer than other switchgear that are prone to arc flash.

In the ring main unit switchgear, the problem of arc flash is quenched by the insulating material, Sulphur hexafluoride (SF6) gas.

This makes the system more reliable.

What is the difference between RMU Switchgear and Circuit Breaker?

The RMU switchgear is fully wrapped, insulated with SF6 gas compact switchgear. T

he RMU switchgear protects and disconnects power from other devices.

A circuit breaker protects an electrical circuit from excess current, thereby protecting it from possible faults.

On the other hand, RMU switchgear de-energizes and protects the whole electrical system from damage.

What is the Voltage Range for Ring Main Unit Switchgear?

The ring main unit switchgear voltage ratings range from 12 kilovolts to 24 kV.

Where can you use the Ring Main Unit (RMU) Switchgear?

RMU switchgear plays an important role in power supply networks.

You can use it in both open-air and enclosed installations.

Normally, you can find them in wind power plants, processing industries, substations, power distribution plants, etc.

They are common inpower distribution networks.