In conditions of unstable power supply, it often makes sense to insure yourself and protect yourself from unpleasant surprises that centralized power grids can present.

For example, you can often observe how the voltage in the network drops or jumps. This can be most clearly seen by paying attention to how it glows ordinary lamp incandescent - if it flickers or burns at full incandescence, there is a problem with your electrical system. Insufficient voltage levels or voltage fluctuations can cause malfunctions of sensitive equipment, loss of computer data, and other unpleasant consequences.

Sudden increases in voltage are also possible, most often caused by short circuits or lightning striking wires or a substation. Despite the measures taken to protect against lightning, such cases occur from time to time and, in addition to malfunctions, can lead to equipment failure.

In addition to the listed network disruptions, it is also possible complete disappearance tension - short-term or quite long. As a result, production is paralyzed, various systems stop working - communications, security, life support and others.

Therefore, in some cases it is necessary to take additional measures and install equipment that will minimize Negative consequences failures of the centralized power grid.

There are two types of such systems - uninterruptible power supply systems and guaranteed power supply systems. Below we will look at how they differ.

Differences between uninterruptible and guaranteed power supply systems

An uninterruptible power supply system most often implies the presence of uninterruptible power supplies (UPS), which, if necessary, switch the equipment powered by them to battery operation. During normal mains operation, the UPS batteries are charged. The UPSs are also equipped surge protectors, which help cut off high-frequency interference in the electrical network, voltage surges, etc.

This measure is effective if your network experiences short-term outages or voltage surges - UPSs cope with such troubles quite effectively. However, in order to maintain the operation of equipment or office equipment during a long outage, the resources of uninterruptible power supply systems are not enough. All they can do in an emergency is give users a few minutes to turn off office equipment normally and save the necessary data.

To withstand prolonged power outages, guaranteed power supply systems, or SPS for short, are required. In addition to uninterruptible power supplies, such a safe system requires the presence of a diesel generator set (abbreviated as DGS), which acts as an emergency power supply unit during a long-term outage of the central power grid, and necessary equipment control and management, which allows the UPS and diesel generator set to interact as a whole.

Design and uninterruptible power supply installation are justified if there are frequent power outages and there are consumers at your site for whom uninterrupted and high quality electricity supply

Under such conditions, losses from failures in the power grid may be so significant that they will exceed the cost of purchase and installation many times over. special equipment, you should also be concerned about installing such a connection scheme at strategic sites or in cases where a power outage could lead to casualties.

The purpose of creating the SGE and the requirements for it

So, in order to create a guaranteed power supply system at any facility, everything is clear - such a system must guarantee a stable, high-quality power supply for responsible energy consumers in the event of incorrect operation of centralized power grids. The result of creating such a system at the facility is to ensure normal operation of the equipment during emergency operation of the central power supply.

When equipping a facility with guaranteed power supply systems, the main groups of particularly responsible energy consumers who need to be connected to a protected electrical network are identified.

First of all, this includes the network equipment that makes up the local computer network - servers, routers, personal computers, etc. Communication equipment (in particular, automatic telephone exchanges), life support systems (ventilation and air conditioning systems), and various medical equipment, on which the health and life of patients depends.

Security and security systems (video surveillance, security and fire alarm, emergency lighting and fire extinguishing systems, etc.), also fully justify connecting to a protected power supply network, since the consequences of failure of such systems can be quite serious.

As for the requirements for the operation of guaranteed power supply systems, the main ones are stable and uninterrupted power supply to all consumers powered by the system, maximum protection against voltage surges and high accuracy of output current parameters in terms of compliance with existing standards.

Also, when designing and creating a guaranteed power supply system, it is important to take into account the convenience and efficiency of use, for which modern SGE have a high degree of automation.

Thus, a necessary condition for such a system is a prompt response to the quirks of the power grid and automatic transfer of consumers to work from a protected network. When the parameters of the central power supply are normalized, the system also automatically turns off.

In addition, it is important to be able remote administration system, if necessary, and the availability of means to inform the administrator about problems that have arisen.

Structure and principle of operation of the SGE

Since each facility has its own characteristics, the configuration of the guaranteed power supply system in each case is developed for specific conditions.

However, despite the fact that quite often when developing SGE it is necessary to resort to non-standard solutions, schematically such systems usually look similar.

The main blocks of the system are, first of all, an autonomous energy source (usually a diesel generator), one or more uninterruptible power supplies (UPS), as well as power supply units direct current. Also similar safe and reliable solution involves the use of system monitoring and management tools and special software.

During normal operation of the centralized power supply network, the diesel generator set is in standby mode, and the power supply to the connected equipment is provided through an uninterruptible power supply. The UPSs themselves in this situation also charge their batteries, acting as a surge protector.

If a failure occurs in the electrical network, the system controller starts the diesel generator; while this is happening, the connected equipment operates from the UPS. After the diesel generator set has reached the specified speed, the load is switched to it, and the UPS batteries are recharged from the diesel engine.

After the problems with the centralized power grid have been eliminated, the controller switches the equipment from power supply from the diesel generator set to the external network. During this process, consumers are also powered by a UPS. Jamming diesel engine installation is also carried out automatically after the equipment has switched to normal power supply.

The autonomous operation time of consumers from the guaranteed power supply system depends on the operating life of the diesel generator set (the volume of fuel in the tank and its consumption) and the capacity of the UPS batteries. If the fuel resource is almost exhausted and the centralized power supply has not been restored, the operator must decide to shut down the work of consumers or continue it until the resources of the diesel generator set and the uninterruptible power supply are completely depleted.

In conclusion, here are some tips on what to look for when choosing an OEM for your equipment: emergency power supply systems.

The main requirements are guaranteed power supply, its high quality and reliability of the supplied equipment, as well as its compliance with domestic standards. Guided by this parameter, it is important to choose serious companies as suppliers that have weight and authority in the domestic power equipment market.

Such companies will also be able to guarantee you qualified technical support and maintenance of the supplied equipment. Finally, when supplying equipment, factors such as prompt delivery and acceptable, economically justified prices for products may also be important.

1.1. The need to create a system

The main problem that one has to face when deciding whether to install a diesel generator set (DGS) and an uninterruptible power supply (UPS) at a facility is the provision of power supply in the event of a loss of voltage from the main supply network of category I consumers and category I consumers of a special group according to PUE.

Unfortunately, in practice, there are frequent situations where the equipment of a distribution transformer step-down substation (RTS 10/0.4 kV or RTS 6/0.4 kV) fails, failures in the area’s power grids, etc. Therefore, 2 inputs from the RTP, as required by the PUE, in practice are not enough and at such facilities there is a need to install a diesel generator station - guaranteed power supply, and uninterruptible power supply sources - uninterruptible power supply.

The guaranteed power supply system serves to provide electricity of the required quality (GOST 13109-87) to consumers of category I (PUE Ch. 1.2.17), in the event of a loss of voltage from the main supply network.

The uninterruptible power supply system serves to provide electricity of the required quality (GOST 13109-87) without breaking the sinusoid of the supply voltage to consumers of category I of the special group (PUE ch. 1.2.17).

2. Description of the solution

2.1. General information

guaranteed power supply to connected consumers;
automatic start (at least 3 attempts in total) of the diesel generator after 9 seconds when the parameters of the main external power supply network deviate beyond the requirements of GOST 13109-87 or its complete disappearance;
automatic load switching from the main external power supply network to the diesel generator and back;
issuing an alarm signal to the dispatcher's post in the event of an emergency event with diesel generator set equipment

uninterruptible power supply (without interruption of the supply voltage sinusoid) to consumers connected via a UPS; Fully adjustable output voltage.
pure sinusoidal output voltage;
high efficiency;
compatibility with diesel generators with a power reserve factor of no more than 1.3;
maximum protection against surges, surges, surges and power outages;
possibility of parallel connection of several UPSs;
possibility of autonomous load support for 20 minutes;
the possibility of uninterrupted switching of the load to power from an external power supply network through the built-in and external bypass;
galvanic isolation of input and output circuits;
remote monitoring and control of UPS parameters.

2.2. Solution structure

Depending on the power supply requirements of consumers, they are used different variants construction of power supply circuits. Let's consider several options.

2.2.1. Using a guaranteed power supply scheme on site

If at a facility only a diesel generator set is used as a backup power source, then such a scheme is called a guaranteed power supply scheme, and consumers receiving power from the diesel generator set in the event of a loss of voltage from the main supply network are consumers of guaranteed power supply.

It is advisable to use such a scheme in cases of frequent loss of voltage from the main supply network and the absence of category I consumers of a special group at the facility, who need power supply for normal functioning without breaking the sinusoid of the supply voltage.

2.2.2. Using an uninterruptible power supply circuit on site

If the facility uses only an uninterruptible power supply as a backup power source, then such a circuit is called an uninterruptible power supply circuit, and consumers receiving power from the UPS in the event of a loss of voltage from the main supply network are uninterruptible power supply consumers.

It is advisable to use such a scheme in cases of infrequent and short-term loss of voltage from the main supply network and in the presence of category I consumers of a special group at the facility.

2.2.3. Combined use of uninterruptible and guaranteed power supply schemes at the facility

If a facility uses both a diesel generator set and an uninterruptible power supply as a backup power source, then such a scheme is called an increased reliability scheme using an uninterruptible and guaranteed power supply.

If the voltage of the main supply network disappears, the diesel generator set receives a command to start it. At the moment of starting the diesel generator set (5-10 sec.), consumers of guaranteed power supply are left without voltage for a short time. Power supply to consumers of guaranteed power supply is restored when the diesel generator set reaches the rated frequency and voltage.

During the startup of the diesel generator set, the UPS switches to batteries, and the uninterruptible power supply consumers are powered from the UPS batteries for as long as necessary to start the diesel generator set. Thus, power supply to uninterruptible power supply consumers is carried out without breaking the sinusoid of the supply voltage.

When the supply voltage of the external power network is restored when consumers are switched from the diesel generator set to the external power supply network, the consumers of the guaranteed power supply are left without voltage for a short time. Thus, consumers' food supply returns to normal. The diesel generator set, after a complete stop, goes into standby mode.

Power supply from the diesel generator set is possible for a period of time determined by the fuel reserve in the fuel tank of the diesel generator set and specific consumption fuel (the value of this parameter depends on the load), as well as the possibility of refueling the diesel generator set during operation. If the power supply from the main input is not restored before the end of the fuel life in the standard fuel tank, the automatic control unit of the diesel generator set will stop the diesel generator.

It is advisable to use such a scheme for objects that require increased power supply reliability.

3. Creation of an uninterrupted and guaranteed power supply system at the site

3.1. Necessary conditions for creating a guaranteed power supply scheme at the facility

diesel generator sets must have a mean time between failures of at least 40,000 hours;
operation of diesel generator sets with a capacity load of less than 50% long time not recommended, and with a load of less than 30%, it leads to the supplier’s refusal of warranty obligations for the equipment;
time for emergency start and load acceptance from standby mode in hot standby no more than 9 seconds.
enable repair work and routine maintenance of a diesel generator set without disrupting the normal operation of the power supply system;
provide remote control of diesel generator set operation;
exclude the possibility of parallel operation of the diesel generator set with an external power supply system;

3.2. Necessary conditions for creating an uninterruptible power supply circuit at the facility

a single failure of any UPS element should not lead to a complete loss of system functionality;
the average service life of the SBP is at least 10 years;
avoiding overloads of neutral cables of input electrical networks and equipment of transformer substations;
work for a long time in the mode of disconnecting the external power grid and providing power to critical consumers from the UPS;
ensuring the possibility of carrying out repair work and routine maintenance of the UPS without disrupting the normal operation of the power supply system;
providing remote control of operation and UPS;
performing the correct completion of technological processes in the event of the disappearance of external power and the expiration of the autonomy resource batteries.

3.3. Necessary conditions for creating a combined uninterruptible and guaranteed power supply scheme at the facility

UPS class - on-line, as the only one protecting the load from all existing problems in the electrical network;
The UPS power is selected based on the load power;
The UPS must be equipped with rechargeable batteries. In general, the battery backup time is selected in the range of 5-10 minutes;
to reduce nonlinear distortions of currents introduced by the UPS into the supply network, UPSs with rectifiers based on IGBTs are used - transistors with 12-pulse rectifiers or with active rectifiers;
It is advisable to select a UPS with a system smooth transition UPS for power supply from battery to mains;
the power of the diesel generator set and UPS is selected in the ratio: diesel generator set/UPS = 1.3;
The diesel generator set must be equipped automatic regulator output voltage and electronic speed controller of the drive motor.

As the experience of the Research Center shows, the choice of parts of the uninterruptible and guaranteed power supply system, taking into account the above requirements, ensures coordinated and stable joint operation of the UPS and diesel generator set. An additional advantage of this scheme over the previous two is the practically unlimited operating time in offline mode, i.e., complete independence of the power supply to the critical load (consumers of category I and consumers of category I of a special group) from problems in the main network.

4. Solution schemes

4.1. Guaranteed Power Supply Scheme

4.2. Uninterruptible power supply circuit

4.3. Uninterruptible and guaranteed power supply scheme

5. Manufacturers of equipment for the implementation of guaranteed and uninterruptible power supply schemes

5.1. General principles when choosing a manufacturer

equipment compliance with Russian standards;
quality assurance and operational reliability;
acceptable delivery times;
literate technical support from the manufacturer.

5.2. Manufacturers of diesel generator sets and uninterruptible power supplies

Having considerable experience in creating guaranteed power supply systems, our company gives preference to such manufacturers as: F.G. Wilson, Gesan, Cummins, SDMO.

When creating uninterruptible power supply systems at sites, our company most often uses APC UPSs; also, Powerware UPSs are used quite often, and less often - Libert.

Oddly enough, but there is a demand for devices that ensure uninterrupted operation computer systems, is growing not only in countries with so-called unstable economies, but also in the West. True, the reasons for this growth are somewhat different. If in highly developed countries maintaining the stability of power supply parameters comes to the fore, then, say, in our country it is the presence of power itself. The issues of justified choice and correct construction of guaranteed power supply systems (GPS) in the relevant documents still remain largely unresolved.

Before moving on to recommendations that are based on practice, we will consider one by one the basic concepts associated with the power supply of a LAN, such as power quality, reliability, a guaranteed power supply system, power supply networks and their types.

Reliability of power supply

The concept of reliability in electrical engineering can be interpreted as the property of an object to maintain, within established limits during operation, the values of all parameters that characterize the ability to perform the required functions in given modes and conditions of use, maintenance, repair, storage and transportation. According to now current rules With regard to ensuring the reliability of power supply, power receivers are divided into three categories and a special group.

Category I power receivers include devices whose power supply interruption could result in danger to human life, significant damage to the national economy, damage to expensive equipment, disruption of a complex technological process or the functioning of particularly important facilities. Their power supply must be carried out from two mutually redundant power supplies (PS) with a permissible break during automatic power restoration.

From category I stands out special group electrical receivers, trouble-free operation which is necessary for an accident-free shutdown of production. Their power supply must be provided extra food from a third independent mutually reserving individual entrepreneur. Its role can be performed by gasoline (BES), diesel (DES) power plants or other energy generating sources.

Electrical receivers of categories II and III include less critical installations, and their consideration is not of interest to us.

Please note that automatic switching on reserve (AVR), which allows you to restore power to category I and even special group power receivers within 3-30 s, only leads to the restoration of power supply, but not to the continuation of their normal functioning. Thus, the reliability categories determined by the current guidelines do not solve the problem of providing LAN with electricity of the required quality. Therefore, it is proposed to introduce an additional group, calling it “a critical group of power receivers of category I to the reliability of power supply.” In this case, we will proceed from the fact that devices belonging to the critical group must withstand a power interruption of up to 20 ms.

These electrical receivers can be divided into two types according to operating modes: devices with normal operating modes and devices with special operating modes. The former must be provided with protection against power failures during a work shift (day) or the time required to complete the corresponding technological cycle; the second - protection against power failures 24 hours a day and 365 days a year. The latter include devices that provide continuous technological process in real time, when interruption is unacceptable, or those electrical receivers, the failure of which leads to the loss of difficult-to-recover information or large financial losses.

To supply power to consumers of the critical group, it is recommended to use SGE as part of an uninterruptible power supply unit (UPS) and an autonomous power source in the form of a diesel power station or BPS. The building should provide electrical rooms with the installation of inlet and distribution boards(electrical switchboard), premises for ABP and for diesel power plants. At the same time, the supply and distribution lines of power, lighting and computer networks must be separated with the mandatory formation of an autonomous power supply network for LAN consumers.

Guaranteed power supply system

Let us define a guaranteed power supply system as a set of devices and circuit solutions designed to provide uninterrupted power supply required quality electrical receivers of the critical group in all modes of network operation (normal, emergency or preventive maintenance nodes and blocks included in the system). Note that SGE is the most important and integral integral part the overall power supply system of the building and ensures the necessary reliability of the entire circuit. The structure of the SGE usually includes automatic transfer switches, power switching devices of the electrical panel room, a distribution network made according to a special design, a UPS, a diesel power station, an autonomous electrical network, as well as lightning protection and grounding devices.

Power supply networks and their types

Currently, there are several ways to implement power supply networks to power power receivers of the critical group.

Net general purpose (regular building power supply network) - a single- or three-phase distribution network in which all electrical receivers are powered from one main panel or line with a neutral (protective) conductor connected to the main grounding loop of the building. In our opinion, the described network organization is unacceptable for LAN design, however, due to the fact that it does not contradict the existing regulatory documents, such networks continue to appear in the solutions of most design institutes.

Dedicated LAN network(executed without additional installation distribution network) - a scheme when LAN power receivers are connected to one dedicated phase of a three-phase main panel or line, and all other power receivers are connected to two other phases. To protect LAN power receivers, the UPS is usually placed between the main panel and the isolated phase. This method of organizing a network is only the first step towards dividing the LAN power supply to ensure the ability to connect a UPS - and no more. The described organization of the distribution network for a large LAN is not recommended.

Split LAN network(additionally installed network during reconstruction) - a construction method in which LAN electrical receivers receive power via a single- or three-phase radial-backbone network, separated from the rest of the general-purpose network. The input feeders of the divided network are connected directly to the main distribution (input) device of the building. To protect LAN power receivers, UPSs are usually placed at distribution panels in nodes of a separated network. This method of organizing the power supply network for LAN electrical receivers can be quite justified, and its cost practically corresponds to the cost of an autonomous network.

Autonomous LAN power supply network(additionally installed during reconstruction or new construction) - an installation scheme in which LAN electrical receivers receive power via a radial-backbone five-wire network, galvanically separated from the general purpose network. It is usually performed on the basis of a UPS that has an output isolating transformer with a star-type secondary winding, the neutral of which is connected to a special process grounding loop with resistance R =< 0,5 Ом.

Of the four types of networks listed above, only an autonomous LAN power supply network makes it possible to supply electrical receivers with electrical energy of the required quality by eliminating stray, pulsed and other currents in neutral conductors.

SGE circuit solutions

Currently, two main SGE schemes are being practically implemented: distributed and centralized-mixed. For all newly built or reconstructed facilities, the most suitable solution is a centralized-mixed LAN protection scheme. In cases where the reconstruction of the power supply system is not carried out, or in case of significant technical difficulties in implementing a centralized-mixed protection scheme, it is permissible to implement a distributed LAN protection scheme as a temporary solution.

Let's consider the scope, advantages and disadvantages of a distributed protection scheme. It can be recommended for a small-scale LAN (20-40 workstations) within one or several floors of a building. In this case, on-line architecture UPSs are used with a standard set of batteries (for 20-30 minutes of maintaining power supply at 100% load) and a common autonomous backup power supply with automatic start when the city power supply goes out and an automatic transfer switch device. Recommended scheme — divided network.

The advantages of a distributed protection scheme include:

ease of installation and extension;
rational planning of funds for the purchase of ABP;
the ability to maneuver when distributing ABP;
no requirements for special training of personnel.

relatively high cost of protecting one workplace;
low level of protection quality and low service capabilities;
when choosing a UPS, the need to provide a power reserve for equipment starting currents;
complexity of centralized management;
lack of flexibility in the use of battery energy of all UPSs;
vulnerability of equipment due to the availability of UPS.

Implementation of the centralized-mixed LAN protection scheme is possible in at least two options. In the first, the protection of all electronic equipment is carried out using a central powerful UPS of on-line architecture with a standard set of batteries for 15-30 minutes of maintaining 100% load and an autonomous backup power supply with automatic start and an ATS device. In this case, LAN power receivers of a critical group with normal operation are additionally protected by nearby less powerful UPSs. The recommended total power of the sources is 15-80 kV*A, and in some cases - even more. Execution method: Autonomous network.

This option has the following advantages:

all LAN equipment is constantly connected to a highly stable voltage source;
overvoltages, electromagnetic interference and voltage pulses in external networks do not affect LAN equipment;
if necessary, carried out autonomous operation from diesel power plants, the duration of which is limited only by the capacity of the fuel tank;
are provided ample opportunities on the use of energy from the central battery (a significant increase in the operating time of the most critical receivers from the UPS when less critical ones are disconnected in an emergency).

In the second option, centralized protection of all electronic equipment is carried out using the parallel connection of several (line) UPS of on-line architecture and an autonomous backup power supply with automatic start when the power from the city power supply and ATS disappears. Recommended if there are electrical receivers of a critical group with special treatment work. Moreover, such devices are additionally protected by nearby less powerful UPSs. The recommended total load power is from 80 kVA*A and above, the implementation method is an autonomous network.

The advantages of the second option include:

permanent connection of LAN equipment to a highly stable voltage source;
no impact on LAN equipment from overvoltage, electromagnetic interference, voltage pulses in external networks and internal general purpose networks;
increasing the reliability of the system as a whole (if one of the UPSs fails) by performing repair work without interrupting the power supply in the autonomous network;
application of a parallel operation control system, which makes it possible to change total power working UPSs by turning on/off one or more of them;
using the energy of a central battery, which allows turning off low-critical electrical receivers in an emergency.

design, supply, installation, maintenance of SGE must be carried out comprehensively, taking into account the parameters of all elements included in it, mutually agreed operating modes and the maximum possible unification;
The autonomous power supply circuit of the UPS LAN devices must have an output isolating transformer with a star-type secondary winding, the neutral of which is connected to a special circuit of the process grounding device with R =< 0,5 Ом. При этом необходимо, чтобы распределительные щитки автономной сети имели защиту от поражения electric shock according to IEC 439-1-85 or GOST 22789-94;
the centralized-mixed protection scheme of the SGE must include a bypass cabinet (SB) and a diesel generator load control cabinet (LOC DG) to make it possible to perform repair and maintenance work on the diesel power plant and set up its operation with the UPS without interrupting the power supply;
ATS switching devices must have mechanical interlocks to prevent simultaneous activation;
LAN power supply autonomy should be ensured not only by separating power electrical networks, but also by eliminating connections between ground loops that can arise through information channels;
Information (overhead) LAN lines laid outside the building or between buildings must be protected special devices overvoltage restrictions.

Practical experience shows that only an autonomous network can fully provide reliable and high-quality power supply to a LAN.

Modern power supply systems are necessary for regulation, conversion and distribution electrical energy, and they also contribute to the uninterrupted supply of different AC and DC voltages. Designed for normal operation of radio equipment, computing and personal computers, alarm and protection devices.

All power supply systems are divided into 3 categories:

Guaranteed power supply system;

Uninterruptible power supply system;

Backup power supply system.

Guaranteed power supply systems

Must provide full guarantee of power supply to connected devices, automatic start-up, automatic load switching from the diesel generator to an external power supply network and vice versa, issuing an alarm if there is a problem emergency situation with equipment.

Taking into account the requirements for power supply, you can use various ways building diagrams. Let's consider a guaranteed power supply scheme.

In the case when only a diesel generator serves as a backup power source at the facility, then this is a guaranteed power supply scheme. Consumers who receive electricity from a diesel generator set in the event of a power outage in the main network are called guaranteed power supply consumers.

It is most advisable to use this scheme when there are frequent voltage outages in the main network, and there are no consumers of category I who need the normal functioning of the power supply without breaking the voltage sinusoid.

In order to create a guaranteed power supply scheme at a facility, the following requirements should be taken into account:

Diesel generator sets must be equipped with a mean time between failures of more than 40,000 hours;

It is not recommended to load a diesel generator set with a load for a long time, the power of which is less than 50 percent. A load of less than 30 percent results in a waiver of the supplier's equipment warranty obligations;

The period of load acceptance and emergency start from standby mode must be less than 9 seconds;

Ensuring the ability to perform repair work and maintenance of the installation without disruptions in the operation of the power supply system;

Providing remote control of a diesel generator set;

Elimination of the possibility of parallel operation of the installation with external power supply systems.

Uninterruptible power supply systems are required for:

Uninterruptible power supply to consumers (there should be no sine wave interruption);

Creating a pure sinusoidal output voltage;

Ensuring high efficiency;

Ensuring compatibility with diesel generators, power reserve factor less than 1.3;

Provisions maximum protection from surges, surges, power surges;

Possible parallel connection multiple power sources;

Providing independent load support for 20 minutes;

Uninterrupted load switching;

Galvanic isolation of output and input circuits;

Remote monitoring and control of uninterruptible power supply system parameters.

Uninterruptible power supply circuit- This is a circuit that uses only an uninterruptible power supply as a backup source. Consumers who receive power from sources when the main network voltage has disappeared are called uninterruptible power supply consumers.

It is more advisable to use this scheme when the loss of voltage from the main network occurs infrequently and for a short time.

To create this scheme, you need to consider the following requirements:

The average period of operation is more than 10 years;

Avoid overloading the neutral cables of the network and the configuration of the transformer substation;

Repair work and maintenance must be carried out without disrupting the functionality of the system;

Creation of remote control of work;

Correct completion of all technological processes.

It is also possible to use a combined guaranteed and uninterruptible power supply scheme. The increased reliability scheme using guaranteed and uninterruptible power has both a diesel generator set and an uninterruptible power supply.

When the main network voltage disappears, a signal appears on the diesel generator to turn it on. During switching on (5-15 seconds), recipients of guaranteed power supply are without voltage for a short period. Restoration of power supply to guaranteed power consumers to normal frequency occurs at the output of the diesel generator.

When the diesel generator set is turned on, the uninterruptible power supply switches to the battery, as a result of which the uninterruptible power supply consumers are powered from the source batteries for the amount of time required to turn on the diesel generator. Consequently, consumers are supplied with power without disturbing the voltage sinusoid.

When the voltage of the external network is restored during the switching of consumers from the diesel generator to the external network, the recipients of guaranteed power for a short period find themselves without voltage. Consequently, consumers are fed in a normal manner. After a complete stop, the diesel generator remains in standby mode.

Power from a diesel generator is possible for a certain period of time, which is determined by the fuel supply and its consumption, as well as the possible refueling of the diesel generator set during operation. This combined circuit is best used at facilities that require increased reliable power supply.

Backup power systems make it possible to avoid troubles associated with power outages. The main positive factors of a modern backup power supply system:

A power outage is not a big deal;

It is possible to add power in case of shortage;

Saving electricity.

The system includes an inverter and a battery pack.

Inverter - responsible for charging the batteries (possibly if it has a built-in charger), converts direct current into alternating current. It is also called an uninterruptible power supply unit, the settings of which control all the main parameters of the system.

Rechargeable batteries- These are energy savers. When the power supply from the central network is cut off, the power switches offline to these batteries. It is also possible to add additional power consumption from them at any time.

At any time, you can add an alternative energy source to the backup power supply system and, as a result, get autonomous system power supply, which makes it possible not to use the central power supply.

Project documentation in pdf

ELECTRICAL PART

1.1. Main circuit

The main circuit of the power plant ensures the delivery of 100% of the calculated operating power in all operating modes of the fish processing complex and may have reserve generating capacity available.

According to the data of consumed electrical loads, the maximum operating power consumption is 2019 kW. The installed generating capacity of the 3 diesel generator sets is 2.44 MW, which provides a power reserve. The diesel generator group always has the option of switching on the diesel station SDMO X1250 with a power of 1000 kW or SDMO V550 C2 with 440 kW.

The switchgear of the guaranteed power supply system (GPS) is made in the form of 3 cabinets connected to 3 sections of the ASU. Cabinets with switches are disabled in normal mode. If there is a power failure in a certain section of the ASU and its absence for a certain time, the corresponding generator starts up and is connected to the section buses while simultaneously turning off the main input of this section.

Switchgears, busbars and power cables selected according to maximum currents short circuit on thermal and electrodynamic resistance.

The switching equipment corresponds to short-circuit currents in terms of breaking capacity.

Local control of generators and SGE circuit breakers is carried out on generator control panels. From the main control panel of the plant in the control room, monitoring of the state of switches and the normal or emergency state of generators is provided.

1.2. Power supply system.

A group of diesel generator sets with an installed capacity of 2.44 MW is designed to operate in emergency mode (no voltage at the main input of the ASU) and is designed on the basis of 2 diesel generators 1250 kVA type X1250 and 1 generator 550 kVA type V550 C2 from SDMO.

3 generators G-1, G-2 and G-3 are connected to 3 sectional busbars of the plant's ASU switchgear.

Automatic switching on of generators G-1, G-2 and G-3 is ensured using a control panel type MICS Kerys from SDMO. Generators are equipped with standard protection kits.

Input distribution devices are designed on the basis of cabinets, devices and busbars from Schneider Electric, installed in a reserve room (29) see “Equipment and cable routes layout plan”. All electrical equipment that may be energized if the insulation is broken is connected to the grounding of the power supply system, which in turn is connected to the grounding device of the plant's ASU.

1.3. Power plant equipment

The guaranteed power supply system (GPS) includes:

2 diesel generator sets X1250 from SDMO with a power of 1000 kW each in container design;

Diesel unit V550 from SDMO with a power of 440 kW in a protective casing;

Input (connection) system for guaranteed power supply;

Diesel fuel supply system for SGE;

Own needs of SGE (cabinet SNGP).

The operating mode of diesel stations is peak.

The GE system is a functional complex that includes, in addition to diesel units, necessary systems input of power supply, automation, control and management.

Total electric power SGE systems -3050 kVA. Type of current - alternating, 3-phase, frequency 50 Hz. Rated voltage - 0.4 kV. Switchgear switchgears are designed for switching and transmitting three-phase alternating current voltage 0.4 kV and 4800 A total current.

A group of 3 diesel generator sets is designed to operate in autonomous mode. Each diesel generator set includes its own Switchgear 0.4 kV for input (connection) of generators G-1 ÷ G-3 to ASU sections.

MICS Kerys control panels are installed at each diesel station. Automated system control (MICS Kerys control panel) provides an operating mode with power generation based on load (within the rated power of the generators).

At the output of the generators, an AIPR type switching unit is installed (for X1250 diesel stations complete with a diesel generator set for the (existing) V550 C2 diesel generator set, an AIPR 1250 A unit is ordered separately.

1.4. Power supply for SGE's own needs.

Power supply for consumers of the SGE's own needs from the ASU is provided according to reliability category I. The auxiliary cabinet of SGE SNGP has two independent inputs from different sections of the plant's ASU and automatic input of a reserve at the input.

On the outgoing feeders of the SNGP it is planned to install circuit breakers for protection against short-circuit currents and overload currents. Cable routes from SNGP are supposed to be made openly in a steel tray on cable shelves and in steel pipes when entering the diesel generator set and passing through the walls.

1.5. Grounding of the guaranteed power supply system.

As a grounding device for the SGE, it is planned to create a grounding device consisting of vertical electrodes of a steel angle l = 3 m, connected to each other by a steel strip 50x5 mm, connected to the grounding device of the plant's ASU.

The resistance of the combined grounding device is no more than 4 Ohms. The project provides for a TN-C-S grounding system.

In the reserve room of the guaranteed power input cabinets, an internal grounding loop is constructed, which is connected to the grounding device and to the metal casings of the power supply input cabinets. In this room, the PEN conductor is divided into PE and N. The connection of the GE input cabinets with the plant's ASU is carried out by 5-wire busbars with separated PE and N.

AUTOMATION

In this set project documentation The following automation and control systems have been developed:

Voltage monitoring system at the main inputs of ASU sections and automatic start-up and connection of diesel generator sets to the corresponding sections;

A system for automatically supplying fuel from a reserve tank to generator tanks depending on their filling.

The automatic start and connection system for the diesel generator set is based on the MICS Kerys control panel included in the delivery package (for the existing G-3 it must be ordered separately).

The automatic fuel supply system is controlled by a special controller for groups of pumps of the SAU-MP type, depending on the position of the level sensors in fuel tanks DSU.

Control of the operation of the SDMO V550 C2 and SDMO X1250 is carried out by connecting the standard control panels of the units to the cable network and transmitting the main “states” of the systems to the control room.

The operator’s workplace is located in the plant’s control room, room 29, see “Equipment and cable routes layout plan.”

When the values of the controlled parameters of diesel stations go beyond the specified settings, the station automation (MICS Kerys) generates an “Accident” event and transmits it to the control room via a cable channel.

The controllers (MICS Kerys panels) are powered from the diesel station’s own needs, and above from the SNGP cabinet.

Blocking a source of guaranteed power supply with a diesel generator. Guaranteed and uninterruptible power supply system