Power supplies do not have absolutereliability and sometimes disabled, which leads to a negative impact on the objects of consumption. For critical devices, this is unacceptable, so they are provided with power from two or more additional sources. When connecting them, AVR devices are used. What it is, explains the abbreviation interpretation - "automatic input reserve". It is a way to create uninterrupted power supply to the consumer with two or more power inputs. This is ensured by automatically connecting the backup input when the main one is lost.
Both power supplies can be connected.at the same time. The disadvantages of this method are high short-circuit currents, high losses and the complexity of network protection. Input reserve is usually made using a switching device, disconnecting the main power source. Power reserve must match the load. If it is not enough, only the most important consumers are connected.
Requirements for ABP
- Fast commissioning after voltage relay trips.
- Inclusion in any cases with the disappearance of the power, except for short circuits.
- The lack of response to the landing voltage at the start of powerful loads at the consumer.
- Single trigger.
Classification
Devices are divided according to the principle of action.
- Unilateral. The scheme contains two sections: power supply and backup. The latter is connected with the loss of the main voltage.
- Double sided. Any of the lines can be both working and backup.
- Recovering AVR. When the main power is restored, the old scheme is automatically put into operation, and the backup is turned off.
- Without automatic recovery. Setting the mode of operation with the main power source is done manually.
The principle of the ABP
In low-voltage networks it is convenient to usespecial relays controlling voltage in protection circuits (AVR circuits, etc.). AVR is preferable here, since not all the equipment can withstand frequent switching power supply. What is AVR? What is it and how does it work? This device is clearly visible by any simple scheme.
- The relay EL-11 controls the three-phase voltage, monitors the phase imbalance, their breakage and alternation.
- Электромагнитные реле с мощными контактами used to connect loads. In normal mode, the coil of the magnetic actuator of the main input is powered from it and its contacts KM 1 connects the power supply to the load.
- When the voltage disappears in the main circuit, the relay KM 1 is turned off, and power is supplied to the coil of the relay KM 2, which connects the backup input.
This scheme ABP can be used in privatehomes, industrial and office buildings, where the switched load reaches tens of kilowatts. The disadvantage of the circuit is the difficulty of selecting a relay for large currents. For switching low-power consumers, it is still suitable, but under heavy loads it is better to take an ATS starter or a triac.
Indispensable sources of additional powerare petrol or diesel generators. The latter are widely used due to their economy and greater power. The market offers a wide range of diesel generator sets (DGS) containing high overload protection systems.
AVR work
How does the ABP work?What is it according to the degree of reliability in the supply of electricity to consumers? Devices are divided into 3 categories. Electricity housing is the lowest. With frequent disruptions in the power supply network, it is better to install a reserve in the house, since the durability of household appliances, as well as comfortable living conditions, depend on it. In the apartment install bespereboynik on batteries, which are mainly used for electronic equipment. Generators are most common as backup power sources for private homes.
Gasoline generator in the simplest versionIt is connected to the power supply of the house through the switch. This prevents a short circuit in case of an erroneous input of the reserve, when the automatic machines for power supply to the house are not turned off. The switch is selected with three positions, where the middle of them completely cuts off electricity.
АВР своими руками можно установить в automatic mode, if the generator is provided with an automatic starting device and is controlled from the cabinet by means of contactors, which also switch inputs. Automatics works on microprocessor control, for example, on Easy controller-controllers. To enter the reserve AVR used voltage sensors. As soon as the power is turned off, the generator engine starts immediately. It takes some time to reach the operating mode, after which the ATS performs load transfer to the reserve. Such delays are permissible for domestic needs.
Automatic generator start unit (BAZG)
AVR is a private house system that providesstart-up and control of a backup generator in the event of a power failure. The latter is completed with a special unit BAZG, which is an inexpensive solution for power outages in the main network. It makes five starting attempts for 5 seconds in each interval after the voltage on the main input disappears. In addition, he controls the air damper, closing it at the time of launch.
If the main entry again appearsvoltage, the device switches the load back and stops the engine of the generator. When the generator is idle, the fuel supply is blocked by the solenoid valve.
Features of the AVR private house
The most common method is with two inputs,where the first one takes precedence. When connected to the network, domestic loads for the most part work on a single phase. When it disappears, it is not always convenient to connect a generator. It is enough to connect another line as a backup. With a three-phase input power is controlled by a relay at each of the phases. When the voltage exceeds the normal range, the phase contactor is disconnected, and the house is powered by the two remaining phases. If another line fails, the entire load is redistributed into one phase.
Для небольшого коттеджа или дачи применяют ДГУ with a power not exceeding 10 kW for a switchboard operating at 25 kW. This generator is enough to provide the house with the necessary minimum of electricity for a short time. When an emergency situation occurs, the voltage monitoring relay switches the consumer's bus to backup power and sends a signal to start the diesel generator set. When the main power is restored, the relay switches to it, after which the generator stops.
Expansion of AVR functions
To control circuit breakers bySelected algorithms are programmed logic controllers (PLC). They already have the ATS program, which only needs to be configured to implement a particular mode of operation. The use of a PLC, for example, an AC500 controller, makes it possible to simplify electrical circuits, although at first glance the device seems complicated. The AVR control can be positioned on the shield door as a set of switches, buttons and displays.
The standard solution already provides software. It is installed in the PLC.
Conclusion
Power outages can lead tovarious negative phenomena among consumers. Most users have only vague ideas about ATS. What is it, many do not know at all and take for a device products that are designed entirely for other purposes. Due to the high cost of electrical equipment, it is important to choose the right automatic transfer switch. Here specialist consultation is required. AVR allows you to improve the performance of household appliances and objects for which the constant supply of power is important.
