Sources of power supply do not have absolute reliability and sometimes turn off, which leads to a negative impact on consumption objects. For critical devices, this is unacceptable, so they are provided with power from two or more additional sources. When connected, ABP devices are used. What is it, the decoding of the abbreviation - "automatic reserve entry", explains. It is a way to create uninterrupted power supply to a consumer with two or more power inputs. This is ensured by automatically connecting the backup input in case of loss of the main one.
Both power supplies can be connected at the same time. The disadvantages of the method are high short-circuit currents, high losses and the complexity of protecting networks. Input reserve is usually made using a switching device that turns off the main power source. The power of the reserve must correspond to the loads. If it is not enough, only the most important consumers are connected.
Requirements for ABP
- Quick reserve input after voltage relay trips .
- Switching on in any case during power failure, except for short circuits.
- Lack of response to a voltage drop when starting a powerful load on the consumer.
- Single actuation.
Classification
Devices are divided according to the principle of action.
- One sided. The circuit contains two sections: power supply and backup. The latter is connected when the main voltage is lost.
- Bilateral. Any of the lines can be either operational or backup.
- Recovery ABP. When the main power is restored, the previous circuit is automatically put into operation, and the backup circuit is turned off.
- Without automatic recovery. Setting the operating mode with the main power source is done manually.
The principle of operation of the ABP
In low-voltage networks, it is convenient to use special relays that control voltage in protection circuits (ABP circuits, etc.). ATS is preferable here, since not all equipment is able to withstand frequent power supply switching. What does the ABP look like? What is it and how does it work? This device is clearly visible by any simple scheme.
- The EL-11 relay controls three-phase voltage, monitors phase imbalance, their breakage and alternation.
- Electromagnetic relays with powerful contacts are used to connect loads. In normal mode, the coil of the magnetic starter of the main input is powered by it and its contacts KM 1 connects the power supply to the load.
- When the voltage in the main circuit disappears, 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 ABP scheme can be used in private homes, industrial and administrative buildings, where the switched load reaches tens of kilowatts. The disadvantage of the circuit is the difficulty of choosing a relay for high currents. It is still suitable for switching low-power consumers, but at high loads it is better to take an ABP starter or triac.
Indispensable sources of additional power are gasoline 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 (DGU), containing protection systems against large overloads.
ABP work
How does the ABP function? What is this in terms of reliability in the supply of electricity to consumers? Devices are divided into 3 categories. Electricity housing is among the lowest. With frequent power outages, it is better to establish a reserve in the house, since the durability of household appliances, as well as comfortable living conditions, depend on this. Uninterruptible batteries are installed in the apartments, which are mainly used for electronic equipment. Generators are most common as backup power sources for private homes.
The gas generator in the simplest version is connected to the power supply of the house through a changeover switch. This prevents a short circuit in case of an erroneous input of the reserve when the automatic machines for supplying electricity to the house are not turned off. The switch is selected with three positions, where the middle of them completely cuts off electricity.
Do-it-yourself ATS can be set in automatic mode if you equip the generator with an automatic starting device and control it from the cabinet using contactors, which also switch inputs. Automation operates on microprocessor control, for example, on Easy relay controllers. To enter the reserve ABP apply 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 switches the load to the reserve. Such delays are acceptable for domestic needs.
Block of automatic start of the generator (BAZG)
ABP is a private house system that provides start-up and control of a backup generator in case of power failure. The latter is equipped with a special BAZG unit, which is an inexpensive solution for power outages in the main network. He makes five start attempts within 5 seconds in each interval after the voltage on the main input disappears. In addition, it controls the air damper, closing it at the time of launch.
If voltage appears again at the main input, the device switches the load back and stops the generator engine. When the generator is idle, the fuel supply is shut off by an electromagnetic valve.
Features of the ABP private house
The most common is the two-input method, where the first one takes precedence. When connected to a network, household loads mostly work on one phase. When it disappears, it is not always convenient to connect the generator. It is enough to connect another line as a backup. With a three-phase input, the power is controlled by a relay on each of the phases. When the voltage goes beyond the norm, 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.
For a small cottage or cottage, a diesel generator set with a capacity of not more than 10 kW is used for a panel operating at 25 kW. Such a generator is enough to provide the house with the necessary minimum electricity for a short time. In the event of an emergency, the voltage control relay switches the consumer 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 ABP functions
To control the circuit breakers according to the selected algorithms, programmable logic controllers (PLCs) are used. They already have the ABP program in place, which only needs to be set up to implement a particular operating mode. Using a PLC, for example, an AC500 controller, makes it possible to simplify electrical circuits, although at first glance the device seems complicated. ATS control can be located on the switchboard door as a set of switches, buttons and indicators.
The standard solution already provides software. It is installed in the PLC.
Conclusion
Failures in power supply can lead to various negative phenomena for consumers. Most users have only a vague idea of ABP. What is this, many do not know at all and take for the device products that are designed for completely different purposes. Due to the high cost of electrical equipment, it is important to choose the right gear for entering the reserve. This will require specialist advice. ATS allows you to increase the efficiency of household appliances and objects for which a constant supply of power is important.