When electricity goes out even for a few minutes, businesses can suffer huge losses. And for hospitals, this situation is simply dangerous. In most facilities it is necessary to ensure uninterrupted power supply. To do this, it must be connected to several sources of electricity. Specialists with this approach use ABP.
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What is AVR and its purpose
Automatic input of a reserve or ATS is a system related to electrical panel input-switching switchgear.The main purpose of the ATS is to quickly connect the load to the backup equipment. Such a connection is necessary when there are problems with the supply of electricity from the main source of electricity. The system monitors the voltage and current of the load and thus ensures automatic switchover to fail-safe operation.
ATS is necessary if there is a spare power source (an additional line or another transformer). If the first source is turned off during an emergency, all work will be transferred to the spare. Using an ATS will help you avoid trouble caused by power outages.
Requirements for ATS
The main requirements for ATS systems are as follows:
- It must have a high recovery rate of power supply.
- In the event that the main line stops working, the installation must ensure the supply of electricity to the consumer from a backup source.
- The action is performed once. Several switching on and off of the load must not be allowed, for example, due to a short circuit.
- The main power switch must be switched on using the automatic transfer system. Until the backup power supply is available.
- The ATS system should monitor the correct functioning of the backup equipment control circuit.
The principle of operation of the automatic input of the reserve
The basis of the work of the ATS is to control the voltage in the circuit. Control can be carried out both with the help of any relays and with the help of microprocessor control units.
Reference! A voltage control relay (also called a volt controller) monitors the state of the electrical potential.In the event of an overvoltage in the network, the volt controller will instantly de-energize the network.
The contact group that controls the availability of electricity plays a major role in the ATS system. In our case, this is a relay. When the voltage is lost, the control mechanism receives a signal and switches to generator power. When the main network starts to work properly, the same mechanism switches the power back.
The main options for the logic of the ATS functioning
ATS system with first entry priority
The essence of the operation of this type of ATS system is that the load is initially connected to the power source No. 1. When an overload, short circuit, phase failure or other emergency occurs, the load is transferred to a backup source. When the power supply on the first one is restored to normal parameters, the load is automatically switched back.
ATS system with second input priority
The logic of operation is the same as that of the previous type of system. The difference is that the load is connected to input 2. In the event of an accident, the voltage switches to input 1. After the voltage on the second source is restored, the voltage will automatically switch to it.
ATS system with manual priority selection
The scheme of the ATS system with manual priority selection is more complex than those discussed above. In this case, a switch will be installed on the ATS system, with which you can adjust the choice of ATS priority.
ATS system without priority
This ATS operates from any power source. In the case when the voltage goes to input 1, and an emergency occurs on it, the load is transferred to input 2.After stabilization of the first input, the mechanism continues to work on input 2. When an accident occurs on the second, the voltage will automatically switch to the first.
Main types of ATS cabinets and shields
ATS shield for two inputs on contactors (starters)
Installing an ATS cabinet on starters is the easiest way to create backup power. This cabinet is the most budget option for installing ATS. As a rule, automatic switches are used in ATS cabinets for 2 inputs. They are needed in order to protect the system from overloads and short circuits. Protection against phase imbalance and power surges is carried out by a voltage relay. In addition, the relays become the "brain" of the entire automatic transfer system.
ATS cabinet with two contactors works according to the following principle. Two contactors are connected to the first and second source, respectively. The first contactor is closed and the second contactor is open. Electricity goes through input number 1.
Attention! In the case when the ATS has the priority logic of the second input, the situation will be reversed: the circuit of the second contactor is closed, and the first contactor is open.
If the current supply at the first input disappears, and at the second it is normal, then the contacts of the second starter will close and the mechanism will switch to it. As soon as the voltage is restored at the first input, the circuit will return to its original state.
With the help of a relay, here you can adjust the delay time with which switching from one source to another will be carried out. The optimal delay is from 5 to 10 seconds, it will protect the system from false triggering of the ATS. False tripping can occur, for example, in the event of a voltage drop.
Reference! In order to prevent both contactors from being switched on at the same time, additional mechanical interlocks are used in ATS shields.
ATS shield for 2 inputs on automatic machines with a motor drive
They are best suited for use with current ratings of 250-6300A. When the current on the main input disappears, special electric motors receive a signal and charge the springs of the emergency switch, switching the load to another input.
The main advantages of ATS cabinets on the motor:
- The resource for reboots is much larger than that of ATS with starters;
- Connecting tires to such a machine is easier;
- The ATS shield on automatic machines can also work in manual mode. In this case, you can enable or disable the machine using special buttons.
The essence of the functioning of this shield is as follows. If an accident occurs at the main input, the automation checks whether input 2 is ready to supply current. If everything is in order, then the spring of the second input machine is cocked, and electricity is supplied. When bushing No. 1 can work normally again, the whole process goes in reverse order, supplying electricity to the main bushing.
On boards with a motor drive, as a rule, a front panel is installed, on which all changes in the ATS can be tracked. And to prevent the simultaneous operation of two circuit breakers, electrical interlocks are often used.
ATS shield for 3 inputs
These cabinets are among the most reliable power sources available. This is because there are two spare lines in the ATS for 3 inputs, which ensures the lowest possible power outage at the facility.Typically, such AVR cabinets are used when interacting with consumers of the first category of power supply reliability. These include such objects, the de-energization of which entails a threat to human life or the security of the state, and can also cause great material damage.
ATS shields for 3 inputs work according to the two most common schemes.
The first is when one section of consumers is powered by three independent lines. Then you can set a priority for one of the inputs, or you can work without priority. The load will be connected where the voltage is normalized.
The second scheme of operation of the ATS shield for 3 inputs is that two sections of consumers operate from two lines that are independent of each other. The third input is connected to a spare power source. In case of an emergency, it connects to one of the sections.
Reference! Such shields can be equipped with both mechanical interlocks and automatic machines with electric drives.
Input-distribution device with AVR
The device is used to receive and account for electricity, as well as to protect buildings from short circuits or overloads. ASU cabinets with ATS are used in AC networks with a voltage of 380/220V with a frequency of 50Hz.
ASU cabinets with automatic transfer of the reserve are a separate panel, where both automatic and manual switching functions, and the electricity consumed on each line is also metered.
ASU cabinets consist of:
- Block of introduction and output of a cable.
- Block of automatic input of a reserve.
- A block where electricity consumption is accounted for.
They can also be multi-panel.Then, in addition, fire panels, distribution panels and others will be installed in them, depending on the requirements for the electrical installation.
ATS shield to start the generator
Additional power from the power generator allows you to almost completely avoid a complete blackout. This is one of the most reliable ways to create an uninterrupted supply of electricity. In this case, the AVR cabinet is necessary to ensure the automatic operation of the generator according to a given algorithm.
The AVR cabinet for the generator can operate in both automatic and manual modes. Initially, it is set to automatic mode, but you can easily change it.
Important! For the correct operation of the AVR-generator bundle, the latter must be able to start automatically.
When input 1 fails, the ATS system will send a signal to start the generator. After the generator begins to function normally, and the voltage at the second input reaches the desired level, the mechanism will switch to a backup source. Thanks to the installed time relay, the second input will not be connected to the generator until it starts to work normally. As soon as power is restored to the main (first) source, the generator will be turned off and power will be switched to input 1.
In manual mode, the generator is switched on and off by pressing special buttons.
BUAVRE
The automatic transfer control unit operates as part of the ATS devices and switches from one source to another.It also monitors the condition of lines, controls contactors and magnetic starters, motors and starts an electric generator.
BUAVR measures the voltage in the phases for a certain period and processes the results in real time. Thanks to this, it can determine the average voltage value in each phase. BUAVR has an increased resistance to overvoltage.
AVR Zelio Logic
Automatic transfer system with relay logic switching between sources. Zelio Logic programmable relay is used. One of the main advantages of choosing such a relay is European quality at a relatively low cost. Also, the Zelio Logic relay is quite simple programming. Basic knowledge is sufficient for correct use. Also, the relay has a graphical interface, which greatly simplifies the interaction.
ATS ATS
ATS ATS are ATS cabinets with intelligent microprocessor units. At the moment, this version of the ATS cabinet is the most expensive on the market. They are most in demand in industrial enterprises, where it is important to ensure reliable uninterrupted network operation and the fastest possible switching to an alternative power source. Some ATSs switch from one input to another in literally two seconds. Also, such blocks do not need additional power. They operate at 480V. You can choose the most convenient algorithm, as well as automatic or manual mode.
