An uninterruptible power supply can be used. A brief educational program on using APC UPS

To ensure that your uninterruptible power supply (UPS) lasts as long as possible and that its purchase brings tangible benefits, follow the tips below for the care, connection and maintenance of the UPS.

Having decided on the question of which UPS is better and having unpacked your long-awaited purchase, do not rush to connect it right away. Before turning on a new uninterruptible power supply for the first time, you must fully charge the batteries. If the new source is immediately put under load, its batteries will not be able to provide the power required to power it.

Figure 1. APC Back-UPS CS-500 equipment

A self-test routine that runs automatically when turned on (except for Back-UPS models) checks whether the battery pack can handle the load applied. If the battery is not charged, the uninterruptible power supply may report that the battery is faulty and needs to be replaced. In this case, you just need to charge the batteries. To do this, connect the device to the network and leave it turned on for 24 hours.

Charging the batteries for the first time takes slightly longer than normal charging. When charging for the first time, the uninterruptible power supply may be disconnected. Some UPSs, for example, from the manufacturer APC, can be charged from the network, regardless of whether the source is turned on or not.

Only equipment that actually requires uninterruptible power should be connected to the power source.

If the device was brought in from the cold, you need to let it warm up for about two hours at room temperature.

The purchase of an uninterruptible power supply can only be justified if a power outage will lead to the loss of important data. Among the devices that require a UPS: servers, personal computers, routers, hubs, streamers, external modems, etc.

Figure 2. Connection diagram for communication devices

Scanners, printers and lighting equipment should be connected to an uninterruptible power supply at your discretion. If the printer turns off during printing, a piece of paper will simply be damaged, but a printer connected to an uninterruptible power supply, at the moment of switching to power from the battery, completely consumes their energy on itself, and thus deprives the computer of protection, which is in dire need of it. Therefore, connect peripheral equipment to the UPS only if you are sure that the battery energy is enough to power all devices.

Figure 3. Connection diagram of the UPS to the computer

If you need to protect equipment that does not carry important information from interference or discharge, it is enough to use a surge filter, such as Surge Arrest, or a network stabilizer, such as Line-R.

Never overload the uninterruptible power supply. Choose a UPS model whose power is not less than the total load power. Don't forget the difference between volt-amps and watts! Be sure to connect the device with a ground connection, as without it the noise suppression efficiency will be reduced. Turn off the UPS only using the button on the front panel. Unplug the cord only if you have to leave your home or office for an extended period of time. Many sources are capable of charging batteries even when turned off.

Most UPS systems decide on their own when to switch to battery power. However, if your source constantly switches to battery operation, it's worth checking its settings. Perhaps the sensitivity of the device or its response threshold is set too high. Don't forget to test your device periodically. The self-test procedure will allow you to be confident that the UPS is functioning correctly and is ready for use at any time.

After about three to six months of operation, the cost of the data stored on a new work computer begins to exceed the cost of the computer itself. In the case of a network server, this situation can arise within a few weeks after its installation.

In 50 70% of cases, the cause of failures in the operation of electronic devices is poor-quality power supply. If there is a power failure, one incorrect data writing session can destroy the entire file system.

Even if failures do not lead to catastrophic consequences immediately, after some time the sensitive electronics of your PC may simply “revolt” due to constant on/off cycles.

In Russia, data from studies conducted in the USA by Bell Labs and IBM have become known. According to Bell Labs and IBM (USA), each personal computer is exposed to 120 power incidents per month.

Why should you use a UPS?

To answer this question, here's what you need to think about:

1. What happens if your facility loses power right now?
2. Have you thought about the harm caused by data corruption or loss?
3. If you have a universal voice and data network, is all your critical equipment protected?
4. If you have virtualized your servers, have you considered the impact on your UPSs?
5. How much power do your UPS modules consume? What is their efficiency?
6. How often do you update and maintain your IT equipment (including servers)? What about your UPS?

UPSs are mainly used to protect IT equipment and other loads from problems that reduce power quality. The UPS performs the following three main functions:

1. Prevents damage caused by power surges and surges. Many UPS models continuously generate the correct output voltage waveform.
2. Prevents data loss and damage. Without a UPS, data stored on storage devices subjected to an improper shutdown may be damaged or even lost completely. In combination with the appropriate software, the UPS can perform a graceful shutdown of the system.
3. Ensures the availability of networks and other applications, preventing downtime. UPSs can also be combined with generators to give the generators sufficient time to start in the event of a power loss.

9 power problems and how a UPS can help you deal with them

Eaton UPS solutions address all nine major power problems. They are designed to meet the power protection, distribution and management requirements of offices, local area networks, data centers, as well as the telecommunications, medical and industrial markets.

For small office and home (SOHO) applications, Eaton offers budget solutions such as the Ellipse and the Eaton 5110 for conventional desktop systems. To protect critical systems such as network servers and high-power blade servers, Eaton offers line-interactive and online UPSs such as the Eaton 5125, 9130, Evolution, EX, MX, MX Frame, 9155, 9355, 9390, 9395 and Blade UPS

Source: EATON CORPORATION. UPS Handbook

Typical power supply problems

Complete loss of mains voltage(no voltage in the network for more than 40 seconds due to disruptions in the power supply lines)

Subsidence(short-term decrease in network voltage to a value less than 80% of the nominal value for a time of more than 1 period (1/50 of a second) is a consequence of the inclusion of powerful loads, externally manifested as flickering of lighting lamps) and surges (short-term increases in network voltage by more than 110 % of the nominal for a time of more than 1 period (1/50 of a second); appear when a large load is turned off, externally appear as flickering of lighting lamps) voltages of different durations (typical for large cities)

High frequency noise radio frequency interference of electromagnetic or other origin, the result of the operation of powerful high-frequency devices, communication devices

Frequency deviation beyond acceptable limits

High voltage surges short-term voltage pulses up to 6000V and duration up to 10 ms; appear during thunderstorms, as a result of static electricity, due to sparking switches, have no external manifestations

Frequency overrun a change in frequency of 3 or more Hz from the nominal (50 Hz), appears when the power source is unstable, but may not be externally visible.

All these factors can lead to failure of fairly “thin” electronics and, as often happens, to loss of data. However, people have long learned to protect themselves: line voltage filters that “dampen” surges, diesel generators that supply power to systems during a power outage on a “global scale”, and finally, uninterruptible power supplies the main tool for protecting personal PCs, servers, mini-PBXs and etc.

Types of Power Failures

Type of power failure	Cause of occurrence	Possible consequences
Low voltage, voltage dips	Overloaded network Unstable operation of the network voltage regulation system Connection of consumers whose total power is comparable to the total power of the electrical network section	Overloading power supplies of electronic devices and reducing their service life Turning off equipment when the voltage is insufficient for its operation Failure of electric motors Data loss in computers
Overvoltage	Underutilized network Insufficiently efficient operation of the regulatory system Disabling powerful consumers	Equipment failure Emergency shutdown of equipment with loss of data in computers
High voltage pulses	Atmospheric electricity Putting part of the power system into operation after an accident	Failure of equipment sensitive to power quality
Electrical noise	Enabling and disabling powerful consumers Mutual influence of electrical appliances operating nearby	Failures during program execution and data transfer Unstable images on monitor screens and video systems
Complete power cut	Trip fuses during overloads Unprofessional actions of staff Accidents on power lines	Data loss in computers Hard drive failure on very old computers
Harmonic voltage distortion	The network is dominated by non-linear loads equipped with switching power supplies (computers, communications equipment) Poorly designed electrical network handling non-linear loads Neutral wire overload	Interference with sensitive equipment (radio and television systems, measuring instruments, etc.)
Unstable frequency	Severe overload of the energy system as a whole Loss of system control	Overheating of transformers Unstable frequency as an indicator of malfunction of the entire power system or a significant part of it (for computers, a change in frequency in itself is not scary)

ANNOUNCEMENTS

Requirements for the quality of electricity are legally prescribed by state standards and fairly stringent regulations. Electricity supply organizations make a lot of efforts to comply with them, but they are not always implemented.

In our apartments, and in production, the following periodically arise:

complete power outages for an indefinite period of time;

aperiodic short-term (10÷100 ms) high-voltage (up to 6 kV) voltage pulses;

surges and drops in voltage with varying durations;

high-frequency noise overlays;

frequency drifts.

All these problems negatively affect the work of household and office electricity consumers. Microprocessor and computer devices are especially affected by the quality of power supply; they not only fail, but can also completely lose their functionality.

Purpose and types of uninterruptible power supplies

To reduce the risk of malfunctions in the power supply network, backup devices are used, which are commonly called uninterruptible power supplies (UPS) or UPS (derived from the abbreviation of the English phrase “Uninterruptible Power Supply”).

They are manufactured with different designs to solve specific consumer problems. For example, powerful UPSs with gel batteries can maintain power supply to an entire cottage for several hours.

Their batteries receive a charge from a power line, wind generator, or other carriers of electricity through the inverter rectifier device. They also feed the electrical consumers of the cottage.

When the external source is turned off, the batteries are discharged to the load connected to their network. The larger the battery capacity and the lower their discharge current, the longer they work.

Medium power uninterruptible power supplies can back up indoor climate control systems and similar equipment.

At the same time, the simplest UPS models are only capable of completing the computer emergency shutdown program. At the same time, the duration of the entire process of their work will not exceed 9÷15 minutes.

Computer uninterruptible power supplies are:

built into the device body;

external.

The first designs are common in laptops, netbooks, tablets and similar mobile devices powered by a built-in battery, which is equipped with a power and load switching circuit.

Laptop battery with a built-in controller is an uninterruptible power supply. Its circuit automatically protects operating equipment from electrical faults.

External UPS Designs, intended for the normal completion of desktop computer programs, are manufactured as a separate unit.

They are connected via a power adapter to an electrical outlet. They power only those devices that are responsible for running programs:

system unit with a connected keyboard;

a monitor that displays ongoing processes.

Other peripheral devices: scanners, printers, speakers and other equipment are not powered by UPS. Otherwise, in case of emergency termination of programs, they will take over part of the energy accumulated in the batteries.

Options for constructing UPS operating diagrams

Computer and industrial UPS are manufactured in three main options:

power backup;

interactive diagram;

double conversion of electricity.

With the first method backup scheme, denoted by the English terms “Standby” or “Off-Line”, the voltage is supplied from the network to the computer through a UPS, in which electromagnetic interference is eliminated by built-in filters. It is also installed here, the capacity of which is maintained by the charge current regulated by the controller.

When the external power supply disappears or goes beyond the established standards, the controller directs the battery energy to power consumers. A simple inverter is connected to convert direct current into alternating current.

Benefits of UPS Standby

Off-Line uninterruptible power supplies have high efficiency when the voltage is applied to them, operate quietly, emit little heat and are relatively cheap.

Flaws

UPS Standby stand out:

long transition to battery power 4÷13 ms;

distorted shape of the output signal produced by the inverter in the form of a meander rather than a harmonic sinusoid;

lack of voltage and frequency adjustment.

Such devices are most common on personal computers.

Interactive circuit UPS

They are designated by the English term “Line-Interactive”. They are carried out according to the previous, but more complicated scheme by including a voltage stabilizer using an autotransformer with step regulation.

This provides adjustments to the output voltage, but they are not able to control the signal frequency.

Filtering of interference in normal mode and switching to inverter power supply in case of emergency occurs according to UPS Standby algorithms.

The addition of a voltage stabilizer of various models with control techniques made it possible to create inverters with a signal shape not only of a square wave, but also of a sinusoid. However, a small number of control stages based on relay switching does not allow the implementation of full stabilization functions.

This is especially true for cheap models, which, when switching to battery power, not only increase the frequency above the nominal one, but also distort the shape of the sine wave. Interference is introduced by a built-in transformer, in the core of which hysteresis processes occur.

Expensive models use inverters based on semiconductor switches. UPS Line-Interactive have faster performance when switching to battery power than Off-Line UPS. It is ensured by the operation of synchronization algorithms between the incoming voltage and the output signals. But at the same time there is some underestimation of efficiency.

The Line-Interactive UPS cannot be used to power asynchronous motors, which are widely installed on all household appliances, including heating systems. They are used to operate devices with power where the power is filtered and rectified at the same time: computers and consumer electronics.

Double conversion UPS

This UPS scheme is named after the English phrase “On-line” and works on equipment that requires high-quality power. It produces double conversion of electricity, when the sinusoidal harmonics of the alternating current are constantly converted by the rectifier into a constant value, passed through the inverter to create a repeated sinusoid at the output.

Here the battery is permanently connected to the circuit, which eliminates the need for its switching. This method practically eliminates the period of preparation of the uninterruptible power supply for switching.

The operation of an On-line UPS based on the battery condition can be divided into three stages:

charge stage;

waiting state;

discharge for computer operation.

Charge period

The sine wave input and output circuits are interrupted by the internal UPS switch.

The battery connected to the rectifier receives charge energy until its capacity is restored to optimal values.

Readiness period

After the battery is charged, the automatic uninterruptible power supply closes the internal switch.

The battery maintains a state of readiness for operation in buffer mode.

Discharge period

The battery is automatically transferred to power the computer station.

Uninterruptible power supplies operating using the double conversion method have lower efficiency in line power mode than other models due to energy consumption for heat and noise. But in complex structures, techniques are used to increase efficiency.

UPS On-line is capable of correcting not only the voltage value, but also its oscillation frequency. This sets them apart from previous models and allows them to be used to power various complex devices with asynchronous motors. However, the cost of such devices is significantly higher than previous models.

UPS composition

Depending on the type of operating circuit, the uninterruptible power supply kit includes:

batteries for storing electricity;

Ensuring maintenance of battery performance;

inverter for generating a sine wave,

process control diagram;

software.

A local network can be used for remote access to the device, and the reliability of the circuit can be increased through its redundancy.

Some uninterruptible power supplies use the “Bypass” mode, when the load is powered by filtered mains voltage without operating the main circuit of the device.

The UPS part has a step voltage regulator “Booster”, controlled automatically.

Depending on the need to implement complex technical solutions, uninterruptible power supplies can be equipped with additional special functions.

Uninterruptible power supply, UPS, UPS- as soon as they call this simple device capable of providing uninterrupted energy supply at sites of special importance. Such facilities primarily include nuclear energy enterprises, oil production and oil refining complexes and social infrastructure facilities.

Equally important is uninterrupted power supply and at home: the effective operation of local computer networks and personal computers directly depends on electricity. In the event of a power outage or a complete shutdown, it will allow the computer to operate for a few more tens of minutes, which is enough to save the necessary data and safely shut down the computer.

It is clear that UPS prices for one computer and UPS prices for large production will differ from each other. Therefore, choosing UPS/UPS, you need to know about certain types of such devices.

Classification and types of UPS

Based on various parameters, UPS It is customary to divide it into several types. If we use power as the determining factor UPS, then among them there are devices of high, medium and low power. This or that power class is used for various purposes, and it is clear that using a power of several hundred watts will not be entirely appropriate for a single computer at home.

Another classifying parameter defining types UPS, it is generally accepted to consider the operating principle of uninterruptible power supply systems themselves. In this regard, the following categories are distinguished: UPS as online (on-line), offline (off-line) and linear-interactive (line-interactive).

Offline uninterruptable power source During normal operation, it provides connection to the main power supply. In emergency mode, the power is switched to backup sources, in this case to batteries. Main advantage UPS The offline type remains its ease of execution and unpretentiousness in operation.

Linear interactive UPS In addition to the switching device, they include an incoming voltage stabilizer. That is uninterruptable power source this type not only provides autonomous power supply devices during a power outage, but also protects against low or high voltage without a general switch to emergency mode.

Online uninterruptable power source built on the principle of double voltage conversion. The AC voltage received at the input is transformed into DC using a rectifier, and then becomes AC again using an inverter. All this helps to establish a stable level of output voltage, and also dampens interference from the main supply network.

Poor quality power supply is one of the main problems of failure of household, office or industrial equipment. Despite the fact that interference that occurs in the electrical network is periodic, it has a detrimental effect on the components of modern electronic devices connected to an outlet. To protect critical equipment or preserve data during a power failure, uninterruptible power supplies are most commonly used.

Basic operation schemes and areas of application of uninterruptible power supplies

The purpose of the UPS is to ensure correct operation of the load during sudden “dips” or “spikes” of voltage, as well as to ensure short-term autonomous operation of the connected equipment during a complete power outage. Modern uninterruptible power supplies are divided into three classes:

1. Backup or Offline
2. Linear interactive
3. With double energy conversion

Their design and functionality are somewhat different, but everyone can figure out how to use an uninterruptible power supply.

Why do you need a backup UPS? Its main area of ​​application is the protection of household computer and multimedia equipment. The scheme of its operation is extremely simple: in normal mode, the load is powered from the network, and when the voltage in it disappears, the device switches to battery mode. The switching time between operating types is non-zero. It is relatively inexpensive and will protect equipment from minor voltage surges and short-term power failures.

The advantages of a line-interactive UPS are smoother signal stabilization and the ability to operate in a wide range of input voltages. Such devices do not allow you to adjust the signal frequency when powered from the mains; when powered by battery cells, they can produce a “pure” or approximate sinusoid. How can I use the Line-Interactive uninterruptible power supply? It is great for protecting monitors, system units, LAN nodes, workstations, computer peripherals and other devices with switching power supplies, which makes it excellent.

The most advanced in terms of equipment protection is a double-conversion UPS. But what is valuable in an uninterruptible power supply developed according to the Online scheme? It is characterized by instant switching between operating modes and independence of the output signal parameters from the parameters at the UPS input. Therefore, this particular type of UPS is designed for switching equipment that is especially demanding in terms of power supply quality. Among the UPS Online topologies, based on the scope of their application, the following types can be distinguished:

Alternative protective equipment options

Many people ask the question: is an uninterruptible power supply necessary if the voltage in the network does not disappear, but simply “jumps”? Do you need a UPS for your computer in this case? The answer to these questions may be a look towards voltage stabilizers. These devices allow you to correct the signal over a very wide range, applying a voltage to the load input at a level specified by the user. This is the main advantage of these devices. The main disadvantage is that the stabilizer stops working simultaneously with the disappearance of voltage in the electrical network. The main problem of stabilization devices is the inability to ensure autonomous operation of the load. Therefore, it is important to clearly understand what exactly the equipment needs to be protected from: from signal level fluctuations or from frequent and short-term power outages. In the first case, the way out of the situation will be a voltage stabilizer, in the second - an uninterruptible power supply, the purpose of which is somewhat broader.

But what to do if the signal level in the power grid is relatively stable, but there are long-term power outages? A way out of this situation may be to purchase a diesel generator. They are available in different power ranges and can be used to service both domestic and industrial facilities. There are diesel and gasoline models. The starter of the device can be either manual or electric. The advantage of using such an installation is that it can provide long battery life for the equipment with breaks only for maintenance or refueling. This equipment is compact, easy to maintain and easy to operate.

The operation of diesel generator sets is not without a number of disadvantages, these include:

• Inability to independently switch to power supply to the load when the voltage in the power supply network disappears;
• Noise during operation;
• Presence of exhaust gases;
• A large number of consumables (candles, fuel, etc.)

Comprehensive solutions for protecting electronic equipment

To ensure maximum protection for telecommunications, server or industrial equipment, using one type of device may not be enough. Therefore, the most optimal solution may be to combine them. For example, a UPS for emergency lighting will not provide the required level of autonomy. This problem is solved by connecting an uninterruptible power supply unit and a diesel generator set in series. Why do you need an uninterruptible power supply in such a scheme? To filter the voltage and ensure autonomy of the system until the generator starts and enters operating mode.

Why and how can you use an uninterruptible power supply in combination with a voltage stabilizer? For the correct operation of equipment in areas of the power grid where there are frequent voltage drops that are not accompanied by a complete shutdown. Due to this, a significant reduction in the cost of the design can be achieved: an inexpensive stabilization device will provide effective signal correction, and a mid-level UPS will allow you to achieve an acceptable level of autonomy.