admin | 29 de April de 2019
Power supply continuity is closely related to devices offering electric protection, another fundamental aspect of any electrical installation Protection devices are responsible for supply outages in our own installation, which may affect several lines depending on which protection device is involved.
Ideally, protection devices should trigger whenever there is a safety risk to those operating the installations or a risk of damaging machinery connected to the network. Having said this, protection devices not only trigger in the event of a real threat, but more often than not transient disturbances with no serious effect on the installation are responsible, and this type of scenario is precisely when protection and power supply continuity come into play.
As a result of the growing demand for solutions that aim to guarantee power supply continuity, devices have been developed to keep installations permanently working without risking personal safety or damage to machinery. Protection devices with self-reclosing systems are responsible for restoring power when there are no longer any risks of doing so. Thanks to such devices, the inconvenience, unnecessary costs and time wasted (in addition to the inherent output losses due to power supply shutdown) in manually switching circuit breakers back on are avoided, especially when they are sometimes located far away, are inaccessible or simply difficult to reach.
They have a wide range of applications since they are suitable for all isolated, mainly unsupervised installations, but where a good balance between safety and power supply continuity is of paramount importance.
Reasons for untimely tripping vary widely. From the presence of harmonic currents in the network to the variable behaviour of loads in the installation, including environmental factors such as lightning during a thunderstorm. As will be seen below, any tripping of protection devices in autonomous installations that are far away or difficult to reach leads to substantial losses for many industries.
Telecommunications centres for telephone, radio and television companies are often located on high ground like hills or mountainous areas to maximise the range they cover. When there are thunderstorms and lightning, any lightning that strikes areas adjacent to these centres could trip the earth leakage protection device. This event, though not causing any permanent system leakage, could render the telecommunications centre useless until a supervisor arrives to switch the circuit breaker back on. Bearing in mind the number of people affected by this type of situation, financial losses for telecommunications companies may reach tens of thousands of euros per minute.
The inconvenience and costs involved in bringing a technician to the area just to find out that the installation has not been seriously damaged must also be added to this cost.
In large cities, order largely depends on how traffic is managed. Correct synchronisation of traffic lights and signalling systems such as luminous panels are crucial for smooth traffic flow in large cities. Anything affecting elements that control traffic would lead to chaos, causing accidents or the busiest areas to come to a complete standstill.
Likewise, most public lighting systems operate independently and are difficult to monitor due to the presence of multiple lamp posts spread out everywhere. As in the case of traffic management, untimely tripping in this type of installation would affect a large number of people and constitute a serious road safety hazard.
Some water and gas supply phases take place in areas that are difficult to reach, thereby making it very complicated to restore supply. Furthermore, the typically slow response time of large companies to restore services could lead to outages lasting even longer.
Turning to other sectors such as food, we have an industry whose needs for continuous power supply are extremely demanding. Take the case of large supermarkets: this type of business cannot afford lengthy power cuts to lines where refrigerating chambers are connected, as this would adversely affect the state of the stored product and may even result in large quantities of goods being thrown away.
Circutor's solution to the above-mentioned problems lies in the use of the RECmax CVM circuit breaker with self-reclosing earth leakage protection and inbuilt measurement.
The RECmax CVM features an electric motor designed to operate the switch when reclosing. Reclosing options (sensitivity, delay, reclosure number, reclosure time intervals, reset times) are programmable and enable fully autonomous power recovery.
The RECmax CVM includes an over-voltage and short-circuit protection device, and also offers earth leakage protection in the event of leakage in the installation. The device guarantees installation safety at all times.
The RECmax CVM features inbuilt measurement for over 250 electrical parameters, thereby enabling a much greater control over the installation's behaviour. The display shows the key variables in your installation, such as voltages, currents, powers, harmonic distortion, power factor... as well as important protection parameters: protection status, real-time leakage, total number of trips or number of trips per protection type. The device allows you to browse different menus using its keypad, which can also be used to configure various reclosing parameters: sensitivity, delay, reclosure number, reclosure time intervals, reset time.
The RECmax CVM's Plug&Play system minimises installation time to just a few minutes. Both the efficient MC measurement transformers and the WGC differential sensor are included in the kit, through which you simply need to feed the power cables, connect them to the device using the plug-in connection terminals, and the device is ready. The aforementioned wiring is all you need for the RECmax CVM to start operating, since it is self-powered through an internal connection to the circuit breaker.
Taking up just 7.5 modules of space for the 4-pole model and 5.5 modules for the 2-pole model, the RECmax CVM is a compact device suitable for installation in switchboards with limited available space.
The equivalent application with separate devices would require 3 more modules and cost 25% more.
The ultra-immunised system, present in other products in Circutor's earth leakage protection range, offers the following advantages:
Thanks to the RS-485 communications port, the RECmax CVM may be added to SCADA systems for remote device management, enabling in-depth analysis of device readings as well as remote configuration. The device features two configurable digital outputs, very useful for controlling alarms or other external systems.
By monitoring the unit, the status of the protection device may also be easily checked at all times, enabling remote intervention.
The backlight display, in keeping with other devices in our company range, allows protection device status to be instantly checked. In the event of tripping, the screen (normally green) changes to red in order to detect faults in the installation at a glance, displaying the value of the current that caused the system to trip.
The RECmax CVM comes in 2-pole or 4-pole versions for all types of installations. Furthermore, the product range includes the possibility to choose from a 6A to 63A current range and a C or D trip curve.
WRITTEN BY CIRCUTOR