For three years I had to live in a country house without centralized power supply and during that time I managed to set up an autonomous energy system that allows my family to live and work at any time of the year.
In modern life, many seek to build country houses and, if possible, spend more time there. At the same time, the energy of the suburbs is developing poorly, equipment in a heavily worn condition, wires being stolen, shutdowns for an indefinite period (as a rule, then, the code is most needed) have become commonplace.
The forecast of the development of the situation is most likely pessimistic - the situation will only get worse and the electricity will go up ...
Those who do not want to wait "By the sea of weather", this material is turned and hope to find like-minded people. Here are some thoughts and descriptions of what has been achieved.
The task of autonomous power supply can be solved in two fundamentally different ways:
- installation is constantly (when necessary) working, which provides all the needs for electricity;
- the creation of an integrated power supply system, which may include a power plant, but it works only when more power is needed or other energy sources are exhausted.
The first method has the advantage that it allows you to not solve many problems and allows you to use standard technical solutions, but has several contraindications:
- a power plant is needed that has a large lifespan, low fuel consumption, designed for 24/7 maintenance-free operation, does not create radio interference, noise and vibrations, and therefore is expensive (although some of these problems can be negated on its own);
- fuel storage is required and, in addition, fireproof;
- to install a power plant, you need a special room that allows you to partly hide the shortcomings of the available power plants. having a good foundation, thick walls, exhaust ventilation, exhaust pipe leading to the sky;
- to eliminate unpleasant odors, it is advisable to install a sufficiently high exhaust pipe, but it will have a problem during operation in winter, consisting in the fact that most of the pipe will not warm up above the dew point and as a result, after the power plant stops, the water that has collected in the pipe will freeze and close pipe.
This problem can be solved by installing a drain valve at the lowest point of the pipe from which to drain the condensate before shutting down the power station or (and) insulating the entire pipe.
It is possible to reduce fuel costs by switching the power plant from liquid to gaseous fuel, which simultaneously reduces the toxicity of exhaust gases, but this method is applicable only to four-stroke engines.
All of these considerations were used when installing the AB-4 power station, which is in many ways inferior to imported ones, but it also has major advantages: low cost, low demand for operating conditions, a large service life, spare parts - it is based on the engine (or rather, its 1/2 part) from 30 - strong "Zaporozhets". The car starter and battery can be easily mounted on AB-4, as a result of which a convenient power station is obtained, which a child can start. AB -4 was installed in the extension to the garage and part of the cooling air flow (it has air cooling) is supplied to the garage in winter. The 3/4 ″ exhaust pipe is connected to the power plant by a stainless steel corrugated pipe section, and a car muffler is mounted on the wall of the room in front of the pipe. The fuel used is propane gas in cylinders of 50 liters each. The power of AB -4 is quite enough for the operation of any power tools, including electric welding. But it is not used constantly. with all the tricks, the noise level is still noticeable especially in the evening in summer, and in winter, when the windows and doors are closed in the house, nothing is heard. In addition, in fact, constantly such power is not needed, and the use of the power plant almost at idle is very impractical - the wear is still going and the efficiency tends to zero.
Therefore, I implemented a more complex version, corresponding to the second method.
To begin with, some existing stereotypes were questioned:
- Current must be variable. This statement was imposed by electrical equipment manufacturers at a time when the only way to change the voltage was to use a transformer. Now, when most devices have transformerless power supply units, they are still fed them with alternating current or alternating current. The easiest way to check whether your device is suitable for DC power supply is to make sure that there is an auto-voltage or to ask a specialist. Naturally, all incandescent lamps, electric heaters and devices with collector motors are perfect for direct current. Having carefully studied the existing appliances, you will see that problems arise only with asynchronous motors, fluorescent lamps, televisions (in terms of the kinescope demagnetization system) and refrigerators. All these problems can be overcome. And therefore, in my house I built two electrical networks: direct and alternating current. Both are 220 volts. As a result, all the lighting and those devices that managed to be adapted for direct current are connected to the first one, and the rest to the second one and work only in the presence of alternating voltage, i.e. when the power station works. Such a scheme allowed the use of 12V batteries with a capacity of 7 Ah from the number of computers used in the devices of guaranteed power supply for storing electricity. They are installed two sets of 17 pieces. Batteries of this type are unattended, sealed, not afraid of full discharge and freezing. They develop a current of up to 30 amps, which at 220 volts gives a very solid power. The electric power stored in them is enough for me with reasonable savings for a couple of days. But still, I prefer to start a power plant for two to three hours once a day and recharge the battery. At the same time, you can perform many jobs for which you need alternating current.
- Second misconceptionthat the refrigerator must be electric. In fact, in the USSR even commercially produced refrigerators that feed on domestic gas — propane. On their basis, electric absorption-type refrigerators were also made: “Frost”, “Frost”, “Ladoga”, etc. The difference was that an electric heater was installed instead of a miniature burner. If you take such a refrigerator, remove the heating element from it, put the igniter from the water heater and bring the exhaust pipe through the hole where the mode switch is installed, you will get an excellent gas cooler that consumes about one 50 liter propane bottle for two months of continuous operation. Naturally, you need to bring the exhaust pipe to the street and comply with other fire safety measures.
Third misconception: The use of DC to AC converters - inverters to power the entire network with alternating current brings more problems than pleasure. This is due to the fact that the current inverters are made, usually with an increase in voltage from 12/24 volts to 220V. Consequently, energy will have to be stored in car batteries with all their disadvantages. (Note. Solarhome: here the author is not quite right - it is not necessary to use automotive AB). Such inverters on sufficient power are extremely expensive and do not tolerate work to an arbitrary load (for example, a refrigerator). (Approx. Solarhome: also a controversial statement - now there are inverters for any purpose in a very wide price range)besides what would not be written in the brochures at their output is not sinusoidal voltage, but rectangular impulses, to which many electric motors refer very badly. (Approx. Solarhome: also a controversial statement - now there are inverters for any purpose in a very wide price range, and non-sinusoidal inverters are gradually becoming a thing of the past). And the most important thing is that in the conditions of rural areas in the zone of uncertain television reception, even a slight level of interference from the inverter makes it impossible for you to watch television (and all your neighbors). Therefore, I had to abandon the use of inverters wherever possible, and if there was no other way, then install self-made transformerless inverters 220 - 220, working for one specific load, and not for the entire network. They are inexpensive and not interfering.- The system of degaussing a kinescope in modern TVs and computer monitors is not needed daily. These devices, like the computers themselves, work perfectly with direct current, and the demagnetization loop must be turned off by placing an additional toggle switch. It can be turned on when the TV is powered by alternating current and turned off at a constant (Note. Solarhome: apparently, this problem is also almost in the past, since TVs and monitors on kinescopes are practically not used anymore - they were replaced by liquid-crystal monitors, also powered by constant voltage).
To get a final idea of the created system, it must be supplemented with a solar battery. True, these units are more in need of refinement, but they still perform their function.
The wind generator charges the battery around the clock (when there is wind), so that by the weekend the battery is fully charged. The wind generator is made completely independently, since everything that is offered by the industry bears a desire for gigantism and is poorly adapted to life. (Note: now it is not so - you can find cheap and high-quality Chinese-made, which are much more efficient than the carousel windmill produced by the author). Therefore, the wind wheel is made of a carousel of fiberglass on epoxy resin and its dimensions are small - 1 * 1.5 m. Such a wheel is able to make and install to any technically trained person. It does not create radio reflections and noise. The installation site — the roof ridge — is least accessible to outsiders and most accessible to the wind. In the future, the wheels will be several, standing nearby. The small size of the wheel determines its low power, but also a small wind load on the rafters and the absence of vibrations. Of course, the power taken from the wheel is small - on average about 30 W, but this is on average - the power depends on the cube of the wind speed. Twice the wind speed - eight times more power. And do not forget that the generator is not used for power, but only for charging the battery. As a generator, a converted car generator is used in which permanent magnets are installed instead of the excitation winding, and the stator winding is rewound with a thin wire. This makes it possible to obtain an acceptable efficiency, because not very significant power consumed by the excitation. The resulting greatly varying wind speed voltage is rectified and converted to a voltage of 220 volts. Wind wheel connected to the generator raising gear 1: 5 and this is a big drawback. I would like to redo the generator by installing more powerful "rare-earth" magnets in it and preferably increasing the number of poles, then it is possible to obtain higher efficiency and effective work with very small winds without a gearbox. (note the site - instead of a carousel-type turbine, it is better to use a Savonius-type turbine, or a propeller turbine - in the latter case, you can safely do without a gearbox and significantly increase the efficiency of wind energy - almost 2 times
The solar battery can well complement the windmill for the same purpose, but with it all the same problems: what is offered is very expensive and has a low voltage. Experiments with a 12 volt low-power battery showed that with a cloudless sky you can count on 12 volts 0.1 amperes, which is quite enough if you install 20 pcs. Such batteries, but where to get them at a reasonable price from the point of view of the buyer? (note solarhome - the situation has changed radically since the article was written - you can find any security systems at an affordable price)
The stated considerations and the results of experiments show that with one or other difficulties, the problem is solved even in artisanal conditions, it is only necessary to break away from traditional ideas. Of course, these are not serial samples, but they have been doing their work for more than one year.
In conclusion, I want to remind you that, in the opinion of a large number of independent experts and mine, the situation in the energy sector will constantly become more complicated and the share of autonomy does not harm anyone.
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Because of this ban, I was forced to use chemical current sources. Specifically, here are these batteries:
At first I was engaged in mechanics and electrical engineering, did various mechanisms with electric motors, but there was nothing to power them. The electric motors were similar (with great difficulty I found a photograph of the engine on the Internet):
It was very interesting to play with hand-made mechanisms. But after a short time the charge ended, because the batteries were not at all like the modern “Duracell”, the engines also did not shine with efficiency, and the design made by the child was far from economical. It was not easy to beg new batteries from adults. They might want to buy them for me, but they sold batteries only in the district center, they traveled 25 km there, not every month someone went there. So I sat on a starvation ration, sorting out the used batteries in a circle, knocking on them with a hammer and pinching them in the front door to at least somehow prolong their work.
Accumulators at that time I saw two types: something like 6ST-55, which were installed in cars, and D-025 disk batteries, which stood in a fashionable flashlight, charged from the network. There was no such flashlight in our family. I knew about them only for the reason that the neighbors gave me for the parts a few of these lanterns in which the batteries lost capacity. And this happened, they said, pretty quickly. In this flashlight, by the way, there was a very unusual rectifier element. Other types of batteries are seen only in the pictures in the books. Therefore, there was no confidence in the batteries, and they were some kind of exotic. There were batteries. Swallowing saliva, I looked at the mechanisms working from the network. What happiness, they could work forever! Since then, a negative attitude towards autonomous power has been developed.
When I went to school, I was allowed to work with the network. The first thing I did was a network laboratory power supply.
Transformer shook himself, and the primary, and the secondary. Iron was taken from the burned-down power transformer of a lamp radiol. My output voltage was regulated by switching the secondary windings. As I recall, with what labors it was possible to find at least one of the materials - horror. All the sheet aluminum, which I owned most of my childhood, it was a lid from an ejected washing machine "Riga". However, now the materials are not much better. The BP transformer was fastened with tin stripes, which were screwed to the wooden base with nails with M4 thread cut into them. Happiness that taps and dies have been with me since early childhood. Galetnik - and the half-homemade. I do not remember for what reason it had to be redone. For the front panel found a piece of blue plastic. In the childhood of such plastic there were large sheets, they were used somewhere in construction. But this plastic was processed very poorly, it was similar in properties to polyethylene. But I had a piece of foil fiberglass! I cut tracks on it and installed a bridge on the D226 and a capacitor. It can be said, the PSU was placed on the PCB! This power unit has served me all the school years and in fact is my most useful design in life. Although in high school I made a new power unit, more powerful, but I still used mostly the old one.
I also had a power supply unit for powering lamp structures (+300 V anode and ~ 6.3 V heat), but this is an industrial design. In some tube radio radiators, the BP was carried out on a separate chassis, and from there I took it. He also had a case with a panel of the same blue plastic, but, alas, there is no photo of the case. In general, all these photos were taken recently, before the devices of the decade were lying in the dust of the attic.
In subsequent years, I made designs only with network power. Autonomous devices - this is something inferior. For example, a portable tape recorder is always worse than a stationary one, and a portable receiver is worse than a radiometer. And well, if the tape recorder has a network power supply. Otherwise, there will be eternal torment with batteries, which, when necessary, are not at hand. Similarly, other devices, for example, measuring. A sign of high class is the network power.
Once again I encountered autonomous power in 1998 when I decided to make myself a generous 30th birthday present and bought a portable Panasonic SL-S200 CD player on the market.
At that time I already had a stationary compact player made from the wreckage of a Sony car player. The case is self-made, the power supply unit and the analog part are self-made, an additional AT89C2051 processor for implementing IR remote control.
Together with the Panasonic SL-S200, the sellers decided to sell me a GP battery and a charger for them. Panasonic itself had a network power supply, but at 110 V. To him, the good sellers gave a small autotransformer, “camelina,” as it was called for the brown color of the plates. I, of course, did not use it, but redid the power supply unit, replacing the transformer in it. The case took from some other adapter, the native was too small. Only the label neatly sawed and pasted into his body.
I also had to immediately abandon the headphones that came in the kit. But I had a Sony MDR-14, bought in a store for $ 16. In general, an interesting time was then - in a store on the central avenue of the capital, they officially traded for dollars. I gave a twenty (and it was then a lot of money), from the cash register I got the change - 4 edinichki. GP batteries did not go to any comparison with the batteries. Moreover, there was nowhere to charge them - the purchased charger emitted smoke when it was first turned on. So I was once again disappointed in the batteries. The player listened mainly at home, feeding it from the network. Mobility needed only within the apartment. I tried to take somewhere with myself, but I don’t feel like listening to music outside. So he spent more than 16 years, almost without leaving home.
The next time when my life again pushed me with autonomous power, it was the purchase of the first Nikon 2100 digital camera. The set included batteries, labeled Nikon. Of course, out of habit, I decided to power the batteries. But was upset by how quickly they run out. Surprisingly, the batteries worked much longer. Moreover, the kit included a quick charger from Nikon too. For the first time in my life I saw something good in batteries. I really wanted to buy the same batteries as a second set. It is unlikely that Nikon makes the batteries itself, most likely takes from someone else. I began to scrutinize the batteries sold. Sanyo batteries were exactly the same, even the letters HR on the bottom were also stamped. Only they had a capacity of 2300, and those with a Nikon label, 2100.
Frightened by bad GP batteries, hesitated to buy these Sanyo for a long time, because batteries are not cheap things. But still bought. In life, joy rarely happens, but here is the case. Purchased batteries worked as long as their relatives.
When it came time to change the camera, the question arose of charging 4 AA batteries. An attempt was made to make your charger as good as purchased. But this attempt failed. I don’t understand how in such a small size a networked impulse fits, and a charging control circuit individually for each of the 4 batteries. As a result of much deliberation, the Duracell charger was written and bought for big money - as much as $ 40.
For a camera, I bought a set of the same Sanyo batteries, then another one - they worked perfectly. One of the sets was very old, it was time to change. But once again, the purchased batteries turned out to be quite weak - about 3 times less in capacity. And in appearance they were no different. The disappointment was huge, because the money spent a lot. But what to do, batteries are needed, I decided to take another chance - I bought a Sony kit. And again failure. Again I got angry at the autonomous power address, but the camera is the rare exception when its operation near the outlet is practically impossible. I read on the forums that solid fakes are now being sold, it is impossible to buy normal batteries. Subtracted that Ansmann, like, until fake. I bought a kit with a modest capacity of 2100 and was pleased. Again at the level of the good old Sanyo.
In a SLR camera, a lithium battery. At first I was worried about this - it is impossible to buy batteries in the nearest kiosk in case anything happens. But the camera is so economical that I forgot the battery problem at all. But the on-camera flash is powered by 4 AA batteries. Also had to buy something. I analyzed the reviews and bought Sanyo again, but now a new line of Eneloop. It turned out great batteries.
Another device, where there is no battery, is a mobile phone. By itself, of course, the phone is not so necessary if you do not work as a dispatcher or a pizza delivery truck, but since there is one, you need to keep it in working order. So you have to regularly buy new batteries. Also come across different quality, nothing can be done about it.
On duty, did a lot of different electronic devices. But almost never made autonomous. Is that a thermometer that is powered by 2 AA batteries or from the network, in connection with which there used a SEPIC-converter, which can both increase the voltage of the batteries to 3.3 V, and lower the voltage of the network adapter.
What am I getting at? Recently, quite often the amateurs are trying to make devices with autonomous power. I do not understand this. There are a lot of problems. It is not enough to provide characteristics, it is necessary to provide still low consumption. Why clamp yourself in such a frame? Well, if someone thinks that he will use the device in the field, he automatically puts himself on the lowest rung of the hierarchy of workers in the industry: living on business trips instead of working in a comfortable office at his own table in a comfortable chair.
P.S. I forgot about one device where autonomous power is justified. This is a clock. As a result of the fact that consumption is small, it is rarely necessary to change batteries (once every few years), this can be tolerated. But there is a downside to low power consumption - on such a clock in the dark nothing is visible.
Today, both private users and large industrial enterprises are striving to have an autonomous source of electricity supply. This is due, primarily, to the possible difficulties of electricity supplying organizations with ensuring uninterrupted supply of electricity. Prolonged interruptions in power supply not only lead to financial costs, but can also be a threat to human life if outages occur in medical institutions or in hazardous and harmful technological production.
The main reasons for the presence of independent sources of electricity
- low quality of current (sharp jumps, drops, fluctuations, etc.) received from the power supplying organization;
- availability of special and first category consumers requiring uninterrupted power supply;
- lack of connectivity to existing power grids.
The main advantage of autonomous power supply is the uninterrupted operation of technological equipment. Autonomous sources can be used both as a primary and as a backup source. An emergency source is equipped with an ATS device capable of supplying to a de-energized section of the power grid in a few fractions of seconds.
Varieties of autonomous sources
The source of electrical energy may be:
- diesel or gasoline generators;
- photovoltaic batteries;
- wind turbines;
- wind turbines.
Engines in power plants can be used as. The first, as is known, are more economical, start up easier, and are characterized by a more significant service life. But their cost is about 2-3 times higher than gasoline ones of similar power. Therefore, diesel power plants are recommended to be used in cases when interruptions in power supply occur frequently enough, which requires long-term station operation. Otherwise, it is better to use gasoline generators.
Today they are installed in private houses and cottages, as a home power station, and can be used as a primary or backup source of power supply. They do not require significant costs for the production of electricity, the generation of electricity in them occurs almost "for nothing". The disadvantages of these devices include a large amount of start-up financial investments, besides the peculiarities of saturation with solar energy create some difficulties in their operation. This is due to the fact that the Sun is able to shine not all year round, but only during the day and only in clear weather, therefore, complete with photovoltaic batteries, batteries are used to accumulate electricity, and converters are devices that convert a constant from batteries to alternating 220V, 50Hz .
- This equipment, which has been used for a long time to generate electricity. Their use is limited by various wind activity of the area and the presence of reservoirs with active moving water flow. Also, their effective operation involves the use of additional equipment (batteries, converters, etc.).
Almost 100% reliability is ensured when working in parallel with external ones. Own generator set provides energy independence, which allows to increase the service life, the duration of the equipment operation period by 25-30%.
With the situation when the power is turned off, everyone has probably come across. And sometimes there is no electricity at the most inopportune moment. In country houses problems with electricity supply is also not uncommon. But what if such situations occur quite often?
Modern technologies have developed so well that a way out of this situation was found - these are autonomous power sources that can be bought from us.
Voltage drops? Autonomous sources of electricity will help!
Sources of backup power also relevant when stretching the power line is simply impossible, or the power supply is simply of poor quality. Each owner of a country house wants to relax and have a great weekend, and without electricity in such situations just can not do. Constant and systematic voltage drops, accompanied by "flashing" of lighting devices, adversely affect the equipment, significantly reducing their service life. Too much spikes can destroy the chips and power supplies.
Functions of autonomous power sources.
In order for all the equipment to work long and smoothly, it is better to use independent sources of electricity. Their main task is to ensure a normal, proper shutdown of electrical appliances in the event of an unexpected power outage. They must also reliably protect the equipment from all types of interruptions that occur in electrical networks, namely:
- voltage spikes;
- high voltage emissions;
- the so-called "subsidence" voltage;
- in case of power failure;
- replanting;
- run out of frequency.
Today, almost every home has a personal computer. According to studies, it is he who is exposed to about 120 abnormal situations every month, the cause of which is precisely the voltage drops.
Uninterrupted power helps to completely forget about all the above problems. The tasks of the UPS are as follows:
- absorb a small amount of short-term surge voltage;
- filter the supply voltage, reduce the noise level;
- provide backup power to the load for a certain amount of time after the loss of voltage in the network;
- protect devices connected to the network from overload and short circuit.
But in order to provide full protection, backup power sources must be connected to the network. The devices themselves are already connected to them. UPS converts the flow of electricity in such a way that it is optimal for the full operation of the device.
Personal power supply system is the best option for a country house.
Autonomous sources of electricity are relevant in the event that it is simply unprofitable for a person to hold a power line and connect to the centralized power supply networks. For example, if you have a cottage that is located too far from the centralized power supply networks, and you go to rest in these places as far as possible, it is better to create your own autonomous power supply system. She will be able to provide you with a number of advantages, namely:
- no need to pay for network connection;
- You will not depend on the price of electricity;
- You will generate electricity when you need it.
What should the autonomous power supply system include?
- Source of energy. As a rule, there may be several or one sources at once. This may be a photovoltaic battery, a liquid-fuel generator GTK, working on gasoline or diesel fuel, or a wind power plant. The main can be any of the above sources, others can be used as additional.
- Battery is a necessary element in the system of autonomous power supply. Even though the main source of energy is available in the system, the presence of a battery will allow it to be turned on for a certain amount of time, and electricity will flow continuously.
- Inverter. It is a device that commutes DC to AC. It is necessary in cases where the equipment in the house consumes 220 V or if consumers are located at a considerable distance. In this case, there are so-called interference and loss.
- AB charge controller. Needed in order to prevent overdischarge and overcharge. Very often, such a controller is built into the inverter.
- Load. During connection to the autonomous power supply system of various devices, it is necessary to know that the devices must be energy efficient. As an example, fluorescent lamps. They are recommended to use for the reason that incandescent bulbs consume 4 times more electricity.
Sometimes it is very difficult to find a company that can offer everything at once. But if you did not find what you were looking for, it is enough to contact our consultant, who will give answers to all your questions.
With us, your devices, even with strong voltage drops, will work stably, and in the event of a total blackout, you will be able to correctly complete the personal computer session and have time to save all the data that might be lost.
In connection with the frequent power outages, unstable voltage and frequency in the power grid, more and more questions have been asked recently: How to provide yourself with electricity for the time when the main power supply is disconnected? Which source of autonomous power to choose? And how to do it?
First you need to decide on the conditions of the problem.
The first condition is load power consumption. This power consists of the capacity of individual consumers of electricity. The number of consumers, from the capacities of which the total load capacity is formed, will depend only on your desire. However, it should be borne in mind that those consumers that you did not include in this list should be disconnected during the operation of the autonomous power source. Failure to do so may result in overloading and even equipment failure.
So you need to understand what you want to get? Ensure a comfortable life at the time of disconnection, regardless of how much the network has been disconnected, or to get along with several especially important consumers, whose disconnection can lead to serious material costs (for example, a heating system).
A country house typically consumes from 5 to 40 kVA. This includes lighting, heating systems, water supply, sewage systems, household electrical appliances, security and fire alarm systems, video surveillance systems.
If you decide to power a part of consumers from an autonomous source (which is reasonable from the point of view of price), then from this entire list you need to choose, first of all, the most critical to the power failure of consumers (emergency lighting, heating system), and then we summarize them less critical loads. Electricity consumers who do not have an inductive component of power, are called active: incandescent lamps, heating devices. However, a simple summation of capacities will be fair until you reach the equipment that has inrush currents. It tends to consume several times the rated current at the time of launch. These currents must be considered and given the appropriate power margin (approximately 2.5-3.5 times). Such consumers are called inductive: electric drills, electric saws, pumps, compressors, refrigerators, laser printers, etc. In addition, it is necessary to take into account the coefficient of simultaneity, which shows the percentage of simultaneous operation of equipment.
Primary Power (Prime Rating Power)- this is the maximum power that a DGU can develop during continuous operation at variable load for an unlimited time.The average load in a 24-hour period is 70%, unless otherwise specified by the manufacturer. Overload for 1 hour at 12 hours of work is not specified by ISO, but is allowed. The minimum value of the load DGU is 25% of the power PRP.
That is, if you assume that your generating set will work as the main source of electricity, then you need to focus on this power. If the PRP value is not specified, then this generating set can operate only as a backup power supply.
Auxiliary and reserve power (Emergency Standby Power)- this maximumwhich DGU can develop when working on variable load during a possible interruption in the power grid, which DGU reserves, with an annual time of no more than 500 hours. Average power over a 24-hour period is 70%, unless otherwise stated by the manufacturer. Overload is not allowed.
The minimum load of DGU is not regulated, but it is 25% of the power of PRP.
That is, this is the power that the generator set can develop for a short time, as a backup power source. ESP power is always greater than PRP power, since it is the power that the generating set develops for a short time (no more than 500 hours per year), but overloading is not allowed.
Thus, the calculation of power consumption is not as simple as it seems at first glance, the task. And we recommend to contact the specialists for correct and correct assessment of power consumption and error-free selection of equipment.
The next important component of the condition of this problem is battery life, that is, the time that your autonomous power supply will work until it recovers and reaches the permissible limits of the voltage of the main power supply network.
To determine this parameter, you need to analyze how often and how much time power outages occur and, based on this, determine the battery life required for you.
Let me explain why this is important. With short-term power failures with a small periodicity, one of the solutions to the problem of autonomous power supply is to install an uninterruptible power supply that uses battery power in autonomous mode, the number of which can be increased depending on the required battery life (up to several tens of minutes). With longer and frequent trips, a solution to the same problem is to install a generator set, for which you also need to provide an adequate supply of fuel, depending on the required battery life.
And one more thing to consider when setting the conditions for this task is the availability of equipment that is critical to various kinds of jumps, pulses, voltage drops and deviations of the frequency of the main power grid. These are electronic control units for equipment (for example, a heating system boiler), computers, alarm and fire alarm controllers, plasma panels, etc. That is, equipment that requires high-quality power supply, otherwise it may not work correctly or simply fail.
Now that the conditions of the problem are known, we can begin to solve it. There are several options for technical solutions.
UPS according to the principle of operation can be divided into two groups: Off line and On Line. Off Line (Stand-By)a type of UPS that allows the load to be interrupted while switching from the input mains to the inverter (transfer time, or switching time). On line A type of UPS that provides continuous and filtered power to the load. By definition, on-line UPSs have zero switching time; load never sees power interruption.
As a rule, single-phase UPS from 4 to 10 kVA of On Line class are used as a backup power source for country houses.
Compared with backup generator sets, UPSs have a number of undeniable advantages.
- significantly higher safety factor;
- long time between failures;
- high quality power output;
- no need for periodic maintenance and replacement of consumables;
- noiseless operation;
- easy connection and installation.
However, to ensure a relatively long autonomy time (from several tens of minutes to several hours), the UPS should be equipped with a sufficient number of batteries (hereinafter referred to as batteries) of a certain capacity, which will most often be limited by the technical capabilities of the UPS, namely the capabilities of the battery charger. In addition, the battery life will depend on several parameters: the load on the UPS, the efficiency of the particular inverter, the ambient temperature, the condition and the degree of battery wear.
Of course, there is the possibility of creating a powerful uninterruptible power system with a long autonomy time. But this raises the question of the economic feasibility of such a decision, and this is an important factor in the process of choosing an autonomous power source.
At present, there are many different kinds of generating sets on the Russian market, a wide range of capacities of a multitude of manufacturers, various versions of which will make even a sophisticated buyer think.
Below we give a classification of the main features of the design of generating sets. And we give a brief explanation, so to speak, at the household level for each of the classification items.
By type of performance
- portable - household, semi-professional and professional gasoline or diesel generator sets with a capacity of up to 12 kVA, can be used as backup power sources; to power consumers with medium and high intensity; for individual activities. They have an air cooling system, they can be with upper or lower valve timing, reliable, convenient and unpretentious in operation.
- stationary - professional diesel power plants with capacity from 10 to 2500 kVA, are used as the main and backup power sources. They have a liquid cooling system, as a rule, with the upper location of valves in the gas distribution system, excellent resource indicators, low operating costs. Requires professional installation.
By way of cooling
- air-cooled - generator sets that are cooled by ambient air.
- water-cooled - generator sets that are cooled with liquid (as a rule, glycol mixtures with water).
Used fuel
- gasoline - generator sets, which use gasoline as fuel.
- diesel - generator sets, which use diesel fuel as fuel.
The frequency of rotation of the engine crankshaft
- 3000 rpm - engines operating at this frequency are cheaper and less, but much more noisy, with higher fuel and oil consumption and have a lower resource;
- 1500 rpm - these engines are quieter, with less consumption and a higher resource. Can be used as a primary power source.
By type of alternator
- with a synchronous generator, have a higher quality of electricity, capable of carrying short-term overload;
- with asynchronous generator, structurally easier and cheaper. However, they have a rather low quality of electrical power at the outlet and are not capable of overloads.
By the number of phases
- single-phase (220 V 50 Hz), only single-phase consumers can be powered from such a generator set;
- three-phase (380 V, 220 V 50 Hz) from such a generator set can be powered as a three-phase consumers, and single-phase. However, it should be borne in mind that the power of one phase of a three-phase station is 3 times less than the total capacity of the installation. It is also necessary to ensure the uniformity of loading of the phases in order to avoid the so-called "skew" of the phases, which badly affects the state of the generating set.
According to the location of the valve timing system
- with lower valve arrangement;
- with overhead valves.
By way of launch
- manual - it is used only for small portable stations, the launch takes place with the help of a cord by unwinding the engine crankshaft to the required frequency for starting;
- electric starter - used for all installations, start-up takes place with the help of electric starter by turning the ignition key;
- automatic - used for installations in which the automatic launch function is implemented. Requires additional equipment. Not necessarily the presence of a person at the start and taking the load.
Now consider the main types of generator sets in the complex.
Generator sets with 2 or 4 stroke gasoline engine
- 2-stroke engines, as a rule, are put only on the most low-power and compact generator sets (time between failures is not more than 500 hours);
- 4-stroke gasoline engines are placed on more serious stations, but not more than 15 kVA (no more powerful than gasoline engines). Time to failure from 1000 to 4000 hours. The main producers are the American company Briggs & Stratton; and Japanese Honda.
Generator sets with 4-stroke diesel engine.
Air-cooled diesel generators are intermediate between gasoline and liquid-cooled diesel engines. Air-cooled diesel generator sets up to 6 kVA are not much different from their gasoline counterparts, although they have a long life and are more reliable. MTBF is more than 4000 hours. The main manufacturer is the Japanese company Yanmar.
More powerful diesel engines with air cooling up to 20 kVA are capricious to the fuel quality, quite noisy and bulky. So in this case it is better to look for an alternative among diesel engines with liquid cooling. The main manufacturer is the German company Hatz.
Diesel engines with liquid cooling are the most reliable and durable. MTBF is up to 20,000 hours. They are industrial grade installations.
The most acceptable in terms of equipment with various options. Major manufacturers from 6 to 20 kVA:
- Mitsubishi, from 20 to 275 - John Deere, from 200 to 500 kVA
- Volvo and Perkins, more than 500 kVA - MTU.
Now let's summarize this solution. With frequent and prolonged power outages or in the absence of an external network, the choice is obvious. However, if we return to the third condition of the problem of consumers critical to interruptions and the quality of electric power, we see that this solution is not very acceptable, since from the moment the voltage drops to the time it is restored by the generator, there is an interruption in the power supply and the generator does not protect against input network distortion.
In order to ensure uninterrupted power to consumers that are critical to the quality of electricity and at the same time have a sufficiently long autonomy time, we recommend using the UPS and GU joint operation. At the time of the power outage of the main power grid, the UPS supplies the most responsible consumers with battery energy. The remaining consumers remain de-energized until the launch of the generating set. After starting the UPS, the UPS goes into normal operation and charges the battery. This is the most acceptable option in terms of reliability.
However, when the UPS and PG are working together, it must be borne in mind that when calculating the PG power, the UPS power calculated earlier must be summed up with the power of the remaining electricity consumers, taking into account the safety factor (1.3-2 depending on which rectifier UPS and whether THD-filters), taking into account the harmonic distortion of the UPS. So, as we see, the solution to the problem of backup power supply is a rather complex and multifaceted task that requires serious study. This takes into account many factors related to both the load and equipment. We recommend that when solving problems of this kind in order to avoid making mistakes and to save your time, consult with specialists.
