Is it necessary to make lightning protection for a diesel generator. Operating modes of neutrals in electrical installations. The grounding system includes

The activities were carried out in accordance with the EMP 7th ed. Chapter 1.7.

Let us consider the case when the object of the protective grounding installation is the DGU container (diesel generator set). In accordance with the customer's data, the soil at the proposed installation site of the EGE-4 grounding device (alluvial sandy loam gray color soft-plastic) and EGE-3 (alluvial-deluvial loam Brown hard plate), ground water at a depth of 2.5m.

Let us take the specific soil resistance equal to 100 Ohm∙m.

In accordance with the PUE, clause 1.7.101, the resistance of the grounding device to which the neutrals of the generator or transformer or the source leads are connected single-phase current, at any time of the year should be no more than 4 ohms, respectively, with line voltages 380V source three-phase current or 220 V single-phase current source.

The DGU container belongs to the ordinary ones in terms of lightning protection in accordance with the Standards and to the 3rd category in accordance with the RD.

Protection of buildings from lightning discharges is carried out with the help of lightning rods. A lightning rod is a device that rises above the protected object, through which the lightning current, bypassing the protected object, is diverted to the ground. It consists of a lightning rod that directly perceives a lightning discharge, a down conductor and a ground electrode.

A set of measures to ensure the necessary requirements for a lightning protection system is represented by the following solutions:

Installation of one lightning rod-mast for 3 concrete bases 4 meters high. Installation is carried out on the roof of the container;

The device of two down conductors with the use of copper-plated wire D=8 mm. Down conductors should be located no closer than 3 m from the entrances or in places inaccessible to people. Mounting of down conductors on the roof is carried out using clips GL-11706. The down conductor is fixed to the vertical surfaces of the building using clamps GL-11704A.

Installation of a grounding device, consisting of five vertical electrodes (copper-plated pins with a diameter of 14 mm.) 4.5 m long, united by a horizontal electrode (copper-plated strip 30 × 4 mm). The distance between the vertical electrodes is at least 5 meters, the distance from the horizontal electrode to the walls of the container is 1 m, the depth is 0.5 meters.

The connection of the down conductor with the output of the copper-plated strip from the ground is carried out using the control clamp GL-11562A.

Calculation of the resistance of the grounding device:

Horizontal electrode resistance:

where ρ is the resistivity of the soil, Ohm m;

b - strip width of the horizontal electrode, m;

h is the depth of the horizontal grid, m;

L mountains - the length of the horizontal electrode, m.

Vertical electrode resistance:

Where ρ eq - equivalent soil resistivity, Ohm m;

L- length of the vertical electrode, m;

d- diameter of the vertical electrode, m;

T- deepening - the distance from the earth's surface to the ground electrode, m;

Where t- deepening of the top of the electrode, m

Grounding device impedance:

Where n- number of sets;

k isp - utilization factor;

The design resistance of the grounding device is 3.89 ohms.

Figure 1 - Protection zone B according to AD

Figure 2 - Layout of grounding and lightning protection elements

Scroll necessary materials is shown in table 1.

Table 1 - List of material requirements

No. p / p	Image	Code	Name	Quantity
1.		GL-21121	GALMAR Lightning rod-mast (4.0 m; on 3 concrete bases; single-stage cable support; galvanized steel)	1 PC.
2.		GL-11149-50	GALMAR Copper-plated steel wire (D8 mm; coil 50 meters)	10 pieces.
3.		GL-11706	GALMAR Flat roof holder for down conductor (D8 mm; for gluing; plastic)	4 things.
4.		GL-11707	GALMAR Decorative protective cover for holder GL-11706	4 things.
5.		GL-11704A	GALMAR Facade clamp for down conductor (painted galvanized steel)	6 pcs.
6.		GL-11562A	GALMAR Control clamp for connecting down conductors wire + strip (painted galvanized steel)	2 pcs.
7.		GL-11075-50	GALMAR Copper-plated strip (30*4 mm / S 120 mm²; coil 50 meters)	1 PC.
8.		GL-11075-10	GALMAR Copper-plated strip (30*4 mm / S 120 mm²; coil 10 meters)	1 PC.
9.		ZZ-005-064

Grounding is a connection electrical appliance with grounding device. Consider how it is carried out in relation to diesel power plants.

Generators, control panel and switchgear must be grounded before starting and operating. This process must be carried out for security purposes, in accordance with the requirements adopted in Russia.

What is a diesel generator ground?

The grounding system usually consists of:

• ground electrode. Most often, steel rods coated with copper are used for this, which are buried in the ground. Note that in this case it is impossible to use pipes of underground water or gas pipelines.
• Grounding copper wire corresponding section. It connects the electrode to the clamp. It is important to remember that the place where the ground electrode and wire are connected must be protected from accidental damage and provided with access for inspection. In this place, according to the requirements, a sign must be placed that says that there is a grounding system here.
• Ground clamp. It is located near the main circuit breaker of the power plant.
• Ground conductor. It connects all non-live metal parts of the installation to the earth terminal.

It is important to know that the connection of the earth clamp to the municipal earth electrode often requires the formal approval of the local authorities. This is necessary in areas where, in addition to the power plant, there is an electrical network common use, and the owner is the only person who is connected to the public supply transformer. Otherwise, you will have to install a separate ground electrode.

The connection of the conductor with the electrodes is carried out by welding, and with generator set- with the help of a special bolted connection on the body of the unit. It is necessary to dig the elements of the grounding system into the ground to a depth of 2.5-3 m.

The number of rods that can provide good diesel generator grounding, is determined depending on the soil. Its loop connection should be small, but sufficient so that, in the event of a ground fault, the current flow will allow the protective devices to operate.

Any installation with a mobile generator must have ground electrodes that are connected to the conductor and neutral. Instrument cables and wires must be as short as possible and free from loops to avoid overheating.

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Diesel generators have a lot of rotating parts, and the laws of physics dictate that friction causes static electricity. Therefore, for safety reasons (avoiding the appearance of sparks from static and ignition), they must be grounded before starting operation.

Grounding device

The grounding system includes:

• Clamp (all conductors are attached to it), it is located near the main circuit breaker of the diesel device.
• Conductor. It integrates the ground clamp with all metal parts that are not energized.
• An electrode representing a steel rod coated with a copper alloy. He burrows into the ground. There may be several electrodes.
• A copper wire of a certain cross section that connects the clamp to the electrode. The place where they are connected must be protected from damage, but free for inspection. Here it is required to install a sign warning about the location of the grounding system “Do not touch. Electrical grounding.

In areas where there is a power grid (public), and the owner is a single consumer connected to a supply public transformer, permission must be taken from the authorities to connect to the electrode (municipal). If permission is not given, a separate earth electrode must be installed.

The conductor with the generator is connected with the help of bolts located on its body, with the electrodes - by welding. Elements of the grounding system are dug in at 2.5 - 3 meters.

Depending on the resistance of the soil, the number of rods for better grounding diesel unit. To protective devices could work (in the event of a malfunction), a loop connection should be sufficient (but not excessive).

If a current leakage occurs during a fault, its level is calculated according to the formula given in the requirement I. E. E. Regulations.

Grounding electrodes connected to the neutral and the conductor must have each installation with a mobile (mounted on a tractor or trailer) generator.

What to use for grounding

For grounding, you can use one of these grounding conductors:

• Galvanized iron (sheet). Its size is 50 cm x 100 cm.
• A metal rod 1.5 - 1.6 cm in diameter, at least 150 cm long.
• Metal pipe (length not less than 150 cm, diameter - 5 cm).

Important: it is forbidden to use pipelines for water and gas for grounding.

Reliable contact connection of the grounding conductor with the ground wire must be provided by special clamps. The other end of the wire is connected to the diesel generator ground terminal. 4 ohms and no more - this is the resistance of the ground loop, which should be close to the diesel device.

The grounding conductor is immersed in the ground to wet soil layers.

Grounding systems

For those operating as stand-alone power sources, an isolated neutral ground is used. For the central network, apply solidly grounded neutral. Grounding systems are:

Important: only a specialist (in accordance with regulations) should ground the equipment and calculate the allowable maximum resistance. The implementation of these actions requires, in addition to high professionalism, the availability of special equipment.

What power to take the generator? How to install it? Where to connect it? What can be connected to an electric generator?... In this article, we have collected the 10 most popular questions and tried to answer them in a simple, understandable language. We hope that the answers to them will help you in choosing an electric generator. Here are 10 basic questions about the generator and the answers to them.

1. How powerful should I get a generator?

The expected power of the generator depends on the amount of electrical loads that you want to use at the same time. Power is measured in Watts (W). First, add up all the loads that you are going to use at the same time. Then, as a precaution, find out which household electrical appliances your home may have high inrush currents (refrigerators, air conditioners, pumps) Add it all to the total.

The fact is that some appliances, such as air conditioners, refrigerators, pumps, tend to use a lot of energy when starting (starting up) - usually 2-3 times more than they use during operation.

You need to make sure that your generator can handle relatively large appliances starting normally, make sure they don't overload the system when starting all the appliances at the same time.

The generator has two units that determine its power: nominal and maximum. The generators are provided with overload protection, which can work at the time of the simultaneous start of electrical appliances. Therefore, you should purchase a generator with some power reserve.

2. What loads should be powered by the generator?

Based on our own many years of experience installing and maintaining generators, we recommend that you provide the main consumers, which include:

1) Heating and all devices related to providing heat (boiler, pumps, etc.).

2) A couple of lighting circuits.

4) Refrigerator.

5) Microwave.

6) Garage doors.

7) Downhole pump.

8) Alarm.

If the power of the backup generator is sufficient, then secondary loads can also be connected: drainage pump, ventilation...

Equipment manufacturers indicate the power of the devices on the devices themselves or in the product passport. Also on many sites you can find an online calculator that will help you choose the power of the generator.

4. Do I need to hire an electrician to connect the generator to electrical network Houses?

Most safe way connecting the generator to the electrical network at home is to use additional device- AVR - automatic switching on of the reserve. The ATS is connected to the mains after the meter, and the generator is connected directly to the automation. When you start the generator, it disconnects the house from the city power grid and powers only those electrical appliances that you have allocated. Thus, the generator will not be overloaded.

If you are an amateur electrician, you have some knowledge of electricity but no experience in installing equipment of this type, it is best to contact a specialist to install the equipment. After all, the reliability of the entire power system of your home largely depends on how competently and efficiently the installation and commissioning of equipment is carried out.

5. Can't I just plug the generator into an outlet?

No and no again! We have already seen many times what this can lead to. This is very dangerous for a number of reasons. For example, if someone forgets to disable the main circuit breaker, then the generator can send power supply to the external network with all the ensuing consequences, if at that time repair work is underway on the line ...

Key points to know for correct connection generators are discussed in this article:

6. What is the difference between standby generator and emergency generator?

The backup generator is installed permanently and is designed to supply most electrical appliances. The emergency generator is a small, portable unit that can be taken outside the premises and connected to the ATS. Or it can be connected to electrical loads via extension cords.

7. If it's raining or snowing outside, can I put the generator in the garage and run it there as long as the door is left open?

No. Never run a generator inside a home, inside a garage, under a shed, on a porch, inside a porch, or near open window. Even with the garage open, carbon monoxide (CO) from generator exhaust can cause poisoning or, in the worst case, death.

8. What other safety tips should I keep in mind?

If the generator is installed permanently, use smoke detectors and carbon monoxide detectors, at least when using the generator. The generator should be located at least three meters from the house to minimize the risks of poisoning carbon monoxide(CO). Never fill the generator with fuel while it is hot.

9. Generators are loud enough. What can be done about it?

Unfortunately there aren't many options. Use generators inverter type, where the speed depends on the load. You can also purchase generators in a soundproof casing. In addition, you can purchase a special soundproof all-weather container in which the generator is placed.

Some craftsmen are experimenting with additional mufflers from motorcycles and ATVs. This can be done if you have the necessary skills. But be aware that in most cases this will void the generator warranty.

The easiest way to reduce noise from a mini power plant is to reduce the electrical load.

10. Do I need to ground the generator?

Follow the instructions in the user manual. If the manual requires the generator to be grounded, do so. The easiest way is to connect a 4-6 mm wire to the ground terminal on the generator. Connect the wire to a copper or iron 1.5 m rod that can be driven into the soil next to the generator.

As an alternative to the ground rod, you can connect the ground wire from the generator to inside the house at the main switchboard.

Most people know that grounding is necessary for safety when installing any electrical appliance, including a power generator. At the same time, few people understand what it is and how exactly the grounding system ensures safety.

So, why is grounding necessary and what will happen if it is not?

To answer these questions, you first need to remember from school course physics, what is electricity- the movement of charged particles in a conductive substance (conductor). The human body is also a conductor of current.

Why is current dangerous? Everyone has heard the expression: "shocked." In this blow lies its danger to a person, starting with unpleasant sensations, ending with a fatal outcome. To receive an electric shock, it is not enough just to touch a wire or part of a live device - it is necessary that there is an electrical circuit.

In practice, there is always such a chain, since we are constantly standing on the ground or on the floor, holding or touching objects. On contact with a wet surface, the potential difference increases and electric shock can be fatal.

In order to protect yourself from electric shock, grounding is necessary. Grounding is a special connection of the electrical network or electrical appliances with a grounding mechanism at a certain point. The essence of grounding is that all metal parts of the equipment are connected to a wire that goes to the ground. It is through this wire that the electric current goes into the soil, and not through a person, thereby ensuring the safety of the latter.

Before starting and starting the operation of the electric generator, it must also be connected to a ground loop, made in accordance with the requirements of the PUE.

• Grounding electrode (ground electrode). Copper-plated steel rods are best suited for this, which are buried in the ground in a certain pattern. Note that in this case it is impossible to use pipes of underground water or gas pipelines.
• Ground clamp. It is located near the main circuit breaker of the power plant.
• Earthing copper wire of the appropriate section. It connects the electrode to the clamp. It is important to remember that the place where the ground electrode and wire are connected must be protected from accidental damage and must be accessible for inspection. In this place, according to the requirements, a sign must be placed that says that there is a grounding system here.
• Ground conductor. It connects all non-live metal parts of the installation to the earth terminal.

In order to effectively carry out all procedures for grounding the power plant and ensure safety, it is necessary to clearly follow all PUE requirements(Electrical Installation Rules) and accurately calculate the maximum allowable resistance. This calculation is only possible when measuring resistivity soil special device at the place of work. Moreover, seasonal factors must be taken into account.

Undoubtedly, the installation of the grounding device should only be carried out by qualified personnel using special tools.