submit

Golovna

Strumi k.z.

call for additional heating of flue-conducting parts of electrical equipment, busbars and cores of electrical cables.

Trivalism, fragments of s.

is indicated by the time it is necessary to connect the lancet with dry devices.

In order to take care of thermal conditions, because

if you were the youngest, turn on the switch.

perhaps shvidshe (an hour of application zakhistu maє perevischuvat 0.1 - 1 z).

Inherited by the short frequency of the circuit.

Please note that all the heat that is seen goes to the heating of the conductors, while when the conductor is heated with a stream, some of the heat that is seen dissipates into an excessive medium.

To simplify the breakdown from calculating the amount of heat that is seen during a short circuit, it is wisely accepted that the heating of the conductor is carried out by a stream, unchanged by the value and equal to the values ​​of the periodic storage because.

In this case, the active hour of action, because

replace with the so-called fictitious hour t f, stretching out some strum I ∞ to see the same amount of heat as the actual one changes because.

After accepting a quantity of heat Q to cal, which is seen by the Joule-Lenz law in a conductor with a support equal to R, with a short circuit:

To avoid short circuits and change their effects, it is necessary to identify the reasons for their occurrence, to correctly design, install and operate electrical installations, three-way transmission, so that all elements of electrical installations (appliances, wiring) ) low dynamic and thermal stability in the minds of short circuits.

.

Select also the tension that prevents the shutter and reliably turn on the defective elements of the equipment or the part of the fence.

1. For what purpose do you need to pay attention to insurance?
2. and determine why they cause a decrease in voltage at the junction nodes.
3. Control food
4. What are the causes of short flickering?
5. What kind of inheritance can lead to a short freeze?
6. What are we called short mutters?
7. What types of short blinks do you see?
8. For which short interruption do the largest streams blame?
9. How are the outer supports of the short-circuit lanyard identified?
10. How do you take the stew during the hour of dehiscence of the streams of a short burst?
11. Is it possible to de-rotate short-circuit currents?
12. What is the process of short fading?
13. How to de-rotate the streams of short-term flashing?
14. What are the peculiarities of short-circuit current flow at voltage levels up to 1000?
15. What is the difference in short-circuit flow rates in named and bearing units?
16. What causes short-circuit currents?

How are electrodynamic and thermal stresses calculated?

How can you ensure the thermal resistance of your equipment?

What parameters of the equipment should be taken into account during the development of short-circuit currents?

The system support Xc is determined by the formula Xc=Uc//√3I(30) The support of the inverted line: inductive Xl = x0l;

active Rl = r0l de x0, r0 - inductive and active line support, Ohm/km (div. auxiliary).

l - Dovzhina line, km.

Inductive support of the windings of the power transformer: Хт = Uk%U1N/√3I1N100%.

The resulting inductive support Chrez - Xs + Chl + Xt Yakshcho Chrez > 1/3rl, then the active support ...

When the conductors pass through an electrical current, the conductors heat up.

When the conductor is heated by a heating stream, part of the visible heat dissipates into dovkill, and the stage of dissipation lies between the ends of cooling.

When a short-circuit current passes through, the temperature of the conductors increases significantly, the fragments of the short-circuit current sharply increase, and the short-circuit strength is small, so the heat that is seen in the conductor cannot be transferred to the excess medium and practically for heating the conductor.

The heating of the conductor during a short circuit can reach unsafe values, leading to melting or carbonization of the insulation, deformation and melting of the conductive parts, etc.

The criterion for thermal resistance of conductors is the permissible temperature of heating by short-circuit currents (x permissible, °C).

The conductor and device are considered to be thermally stable, since the heating temperature during the short circuit process does not exceed the permissible values.

The most complex is the decrease in the value of the Joule integral during a short circuit near generators and synchronous compensators.

However, in the initial design, here you can quickly calculate the formula (4.1.3.), so that the meaning of this value will be further protected, and the conductors and devices installed in permanent connections (generator, transformer, coupling, etc.) are in the minds of the trival In the mode of electrodynamic resistance, significant reserves of thermal resistance are maintained.

Coming from the genital deposition, the formula (4.1.3.) as T a.eq can be taken to the maximum value of T and those devices that support the place of KZ, such as sprat, which leads to an increase in the Joule integral and does not give damages during testing of devices for thermal resistance.

When the Joule integral is defined, it is necessary to accurately determine the value of the incl.

Conclusively up to PUE, the short-circuit failure t switch is formed from the hour of the main relay protection of this lancet (t pz) with the regulation of the automatic recloser and the permanent switch-on time of the circuit breaker (t switch), as indicated in the catalog data vimikachiv, s,

t off = t pz + t off (4.4.)

For Lanzug generators with PnomG?

60 MW PUE is recommended to be accepted t off = 4 z, then.

after an hour there will be a reserve protection.

The production plants in the catalogs indicate the values ​​of the guaranteed mean-square thermal resistance (t ter, kA) and permissible flow rate (t ter, s) for electrical equipment (vimikach, switchgear, transformers, etc. In.).

In this case, the thermal resistance of the devices in short circuit mode looks like 2 * s, B before?(seconds or parts of a second) are heated by the short circuit.

from a given core temperature θ n to a temperature of max.

Strumi k.z. B before? In many cases, there are more currents in normal mode, therefore, regardless of the low severity of the short circuit, the temperature of the conductors rises sharply and θ max becomes much higher than θ N (Fig. 6.1). Temperature values ​​θ max and leveling її with short-hour permissible thermal expansion for short-circuit mode.

Fig.6.1 Heating of the conductor in short-circuit mode

Not a great hour

short circuiting allows for thermal recovery during short circuits.

without providing heat to too much of the stomach in one hour.

Let's take a look at the heating of the conductor of the periodic storage current of the short-circuit, having deprived the additional heating of the aperiodic storage current of the short-circuit.

Such a separate look at two warehouse struma k.z.

It is possible that it bezpredno viplyvaet z viraza for struma short zamikanya I k.z. : I 2 k.z = I 2 p t + I 2 at (6.1)

where I at is the value of the aperiodic storage, and I p t - the periodic storage.

The energy spent on heating the conductor with the flow t p t is expressed by Lenz’s law.

Then the output pattern of heating the conductor looks like: i 2 n t R np t = C m θ (6.2) de R np - conductor support, C - heat capacity of the conductor material, m - conductor water.

I look at those whose flow changes over the course of an hour. Then the output pattern of heating the conductor looks like: and the thermal capacity and support of the conductor is a function of temperature, resulting in a differential heating level:

i 2 p t ρ about (1+ αθ) dt = s lγc o

(1+ β θ)d θ (6.3) de i p t - Mitteve value of periodic warehouse k.z.ρ about (1+ αθ) - conductor support at temperature θ about C, ohm γ c o

(1+ β θ) - additional heat capacity of the conductor material at θ about C

, Tue. s/r. about Zρ about i

– pitomy opir and heat capacity at 0 about C s/r. about Z = γ

α and β temperature coefficients of change ρ and

c

s

l – B before? conductor's obligation, cm 3; - Manager tobto.

area OABC = dt

The same amount of heat can be seen in the constant flow of the circuit. B before? I 2 ∞ already in another hour B before? fp. B before? You can know this hour by visiting the evenly sized ODEF. B before? For special purposes

B before? FP for the singing hour

behind the rozrahunkovy curves of the strums k.z.

caused by staleness

fn = f(λ) (Fig. 6.3), and λ = I” / I∞.

This way you can calculate the integral as:

fp (6.6) Fig.6.3 Fictitious hour curves The heat that appears to be an aperiodic short-circuit storage stream. (6.8)

– pitomy opir and heat capacity at 0 about C i and t are defined in the same way up to level 6.6: t f.a.

(6.7)

de t f. - The hour it took for the circuit to set up.

see the same amount of heat as the aperiodic storage flow of the short circuit. B before? under the hour of short freeze t. B before? The aperiodic warehouse extinguishes from the stationary hour of the Lanzug to the short-circuit point.

T a: i a t = √2

I" o e - t/Ta / I" o – (6.10)

in view (level 5.9) of the importance of the supra-transitional storage struma k.z.

at the time of the hour that is equal to 0. This function is easily integrated and results in the value of the fictitious hour of the aperiodic warehouse:

t f.a = T a λ 2 (6.9) de λ =

I"o/ New fictitious hour

f =

fp + t f.a

Due to the fact that the duration of a short freeze is small (does not exceed a few seconds), temperatures that are significantly higher than the permissible temperature during dry heating are required.

In this case, it is ensured that the insulation of the conductors is designed to be maintained without harm for further work.

For bare conductors (busbars of separate devices), the mechanical value of the material must be taken into account.

For example, for bare copper tires the maximum value is 300 °C.

Fluid ducts that are protected by jetters need not be checked for thermal resistance, just like ducts that are protected by flue-interchangers and vimikach, without special testing when required.< (I 2 t) доп. ,

Selective automatic machines (automatic machines with a visibly switched on time when the short circuit is switched on) are checked for thermal resistance at the washbasin

I 2 ¥ t f

de I ¥ - Insertion of strum k.z.;

t f - fictitious short-circuit hour; (I 2 t) add.- Thermal resistance according to technical minds (previous data). ELECTRODYNAMIC ACTION OF STRUM K, W, When the struma is pierced i in the circuit, the electrodynamic force remains responsible F, so that the contour is deformed (Fig. 6.5). ELECTRODYNAMIC ACTION OF STRUM K, W, With a steady value of the stream, the field energy increases

W(6.11)

– pitomy opir and heat capacity at 0 about C F when deforming the contour in a straight line

X

one robot, with thorough electromagnetic force

for that same hour. i dW = Fdx - The coordinate is direct force. Rising 6.11 is called Maxwell's Rising. (I 2 t) add. Small

ELECTRODYNAMIC ACTION OF STRUM K, W, = (6.13)

6.5 Action of electrodynamic forces on the circuit behind the strum. Magnetic energy in a circuit with inductance (I 2 t) add. L and the room is indicated by the familiar expression: With two circuits with inductances L 1 and L 2 i above all strums

1 ta i 2 and mutual inductance(6.14)

M magnetic field energy is indicated by viraz: W= L 1 i 2 1 +

L 2 i 2 2 + M i 1 i 2 (6.15)

Electrodynamic force, which cannot be changed by mutual expansion of hard circuits (

L 1 = 2const;(L 2 = - const) is older:

F = i 1 i 2 10 -7 (6.17)

і The mutual inductance (H) of two parallel conductors located in the same area on the riser is much smaller, lower than them. M=

l

When the mechanical function of the tires is different, the short-circuit mode comes out of the assumption that the skin-phase tire has a rich running beam, which must lie firmly on rigid supports and be under the evenly distributed base tazhennya

Spreadsheet tires.

are satisfied with the electrodynamic stability, since the maximum permissible voltage in the bus is less or higher than the maximum permissible voltage, then.

σ rozr.

≤ σ add.

a) change in the value of the short-term flow;

b) increased distance between tire axles;

c) changing the flow between the supporting insulators;

d) change the tire cut size.

The maximum voltage in the tire when the tires are rotated flat is determined according to the following conditions:

When the number of spills is more than two

σ rozr.

= (1.06 K f i 2 r L 2 / a h 2 b) * 10 -10 kPa (6.19.)

with the number of spills that are equal to two

σ rozr.

= (1.33 K f i 2 r L 2 / a h 2 b) * 10 -10 kPa (6.20)

When rotating the tires, follow Fig. 6.6 a.

maximum voltage

the tire has one thing: .

σ rozr.

= (1.06 K f i 2 r L 2 / a h b 2) * 10 -10 kPa (6.21)

with the number of spills that are equal to two,

σ rozr.

= (1.33 K f i 2 r L 2 / a h b 2) * 10 -10 kPa (6.22)

de i r – the back shock stream of a short wave;

a - stand between the phase axes, cm, set a = 6...7 cm< i уд. доп. ;

L - Dovzhina spill, cm, zazvichay L = 60 cm;

h-tire height, cm;< I t доп,

b – tire thickness, cm;

K factor is the tire shape coefficient, which is determined from the curves presented in Fig. 6.7 Smallι 1 and ι 2, then these conductors feel one to one gravity it looks evenly divided Sustainable mechanical linear vantagement f [N/m], which is more ancient

F = 2∙10 -7 to f, (6.32)

de 1, 2 - streams in conductors, A;

a - stand between conductors, m 2;

to f – coefficient for the unevenness of the subsection of the strum behind the conductor cut (to f ≈ 1 for round, square and tubular cuts at U< 6 кВ и для любого сечения при U >6 kV;< 6 кВ для плоских шин к ф определяется по справочным кривым в зависимости от размеров сечения и расстояния между шинами).

at U

With a 3-phase short circuit and a distribution of conductors in one plane, the middle phase experiences the greatest strength in the short circuit.

Maximum (shock) linear mechanical force for this phase is older

F beat = 10 -7 to f.

(6.32)

Mechanical pressure demands a critical moment on hard conductors (tires).

If there is an indefinitely long expansion conductor on evenly spaced supports (Fig. 6.2), the maximum moment at the support itself is M max, [N∙m] i.e.

M max = , (6.33)

l – span between supports, m.

conductor fixed on evenly spaced supports

When there is a moment of tension in the metal, a mechanical stress arises, σ, N/m 2 or MPa.

The highest mechanical stress in metal when the metal is destroyed de W - moment of support, m3. The support moment is determined by the dimensions of the conductor and the direct force applied to the conductor (the method of spreading the tires, Fig. 6.3)

Small 6.3. Rotating of tires on insulators:

a – flat;

b – on the edge

When rotating the tires on the insulators, lay flat (Fig. 6.3,

A

), the moment of support is older

When rotating the tires on the edge (Fig. 6.3,

b

) the moment of the support is old

The maximum voltage values ​​for the metal tires σ will be less than the permissible voltage values ​​σ additional for this material, then.

σ rozrahunki ≤ σ add.

(6.36)
The end of the robot -

This topic belongs in this section:
The power supply systems (SES) of industrial enterprises will evolve with the development of electricity supply.

When reconstructing (SES) and designing new systems, the main problems are likely to be affected
Enterprises

Let's take electrical energy into the electrical part of the technological installation or mechanism, which takes energy from the circuit and spends it on the development of technological processes.
Characteristics of EP industrial enterprises

Let's take a look at the characteristics of the group of industrial enterprises using electrical energy.
1. Power ignition installations.

This group of receivers of electrical energy must be
Modes of robotic electrical devices

The correct design of electrical connections (ENG) is the most important and important step in the design and operation of electrical supply systems.
Electrical installations are characterized by

Methods for designing rozrakhunkovih navantazhen
For the expansion of electrical equipment in industrial enterprises, two methods are important: the drinking coefficient method and the expansion coefficient method.

To additional methods
Cost of electricity consumption

The total intensity (active, PΣ and reactive, QΣ) on busbars with a voltage greater than 1000 V is indicated by the relationship: PΣ = (Σ
Elements of electrical fencing

Industrial enterprises consume approximately 10% of the electricity that is transmitted.
The amount of costs depends on a variety of factors, but is primarily determined by the operating mode of electrical appliances and

Ways to reduce EE consumption in electrical supply systems
Electrical consumers of industrial enterprises operate their robots in both active (P) and reactive (Q) tension.

The reactive force vibrates, as it is active, by synchronous generators
Electrical installations and electrical circuits with voltages greater than 1000 V, usually with PUE, are divided into installations with large ground fault circuits (single-phase short circuit current)

Open and closed boundaries
Non-closed (closed) are called boundaries, lines that create closed contours.

Such networks are formed by one main life core, connected to one of the nodes of the network.
Types of conductors to discuss

For the installation of electrical connections, uninsulated (naked) and insulated wires, cables, and jet ducts must be assembled.
Naked darts do not stain insulating covers.

Ix
Electrical wiring using insulated wires

Electrical wiring is usually called permanent and alternating current circuits with a voltage of up to 1 kV, which are made with insulated wires, as well as cables with small overcuts (up to 16 mm2).
Cable lines

The cables are installed within the limits of industrial enterprises of all voltages (up to 110 kV inclusive) both in the middle of the dispute and in the territory of the enterprise and at the current power supply.
Busbar

Busbar is the name given to power transmission lines, such as hard buses.
Busbars may be exposed (non-insulated busbars on support

Damaged lines
A power transmission line (PL or VLP) is called a device for transmitting electricity through wires.

Submarines can be used in high and low voltage ranges for separation.
Short breaks in electrical circuits

Short faults (SC) are called spontaneously or intermittently, not transmitted by normal minds of robots, the connection of two points of an electrical circuit through even a little
Destruction of the short-circuit line from constant periodic storage

The periodic supply of short-circuits, which is consistent with the losses that are allowed, can be kept practically unchanged in the hours when their changes are lost within 10%.
Yakshcho races

Rozhrakhunok struma KZ from changeable periodic warehouse
Shop substations live with the PN limit.

At workshop transformer substations with a voltage of 6-10/0.4 kV, circuits without HV busbars are usually installed.
Transformer circuits

Schemes of the main low substations
For reliable feeding of households of categories I and II, low substations (GPP and PGV) are usually equipped with double transformers.

Living substations in power systems
Main electrical substation

The main electrical equipment of the substations includes: power transformers, switching devices, disconnectors, insulators and busbars of separate devices, vibrating transfers.
Insulators and busbars of subdivisions

Power-conducting parts of electrical installations are fastened and insulated using one type of insulator.
Insulators are divided into line, apparatus, support and feedthroughs.

When reconstructing (SES) and designing new systems, the main problems are likely to be affected
Linear isolators

7.4.

Inspection of cable ducts for electrodynamic resistance in case of short circuit

8.1.1. The characteristic characteristics of rozrakhunkov's programs

Zmist

To check conductors and electrical equipment for thermal resistance during a short circuit, it is important to use the rotary diagram and the short circuit point, and the rotary type of the short circuit and the rotary phase of the short circuit.

A multi-phase short circuit during re-inspection of conductors and electrical equipment of electrical installations with a voltage of 110 kV is mostly a tri-phase short-circuit, in electrical installations over 1 kV up to 35 kV - a three-phase short-circuit, and in electrical installations a generator voltage dance - either three-phase or two-phase depending on how to produce them to a large thermal infusion.

8.1.2. Rozrakhunkov's short-circuit severity when testing conductors and electrical devices for thermal resistance during short-circuit follows the given hour of the main relay protection, to the zone in which the conductors and devices enter Please ensure that the nearest short-circuit connection is switched on at all times, and when the cables are reconnected non-burning - the added time for the backup relay protection and the permanent connection of the power supply.

Values ​​of the reduced weight coefficient g for different wines Mg/m

8.2.1. When a short-circuit current passes through, the temperature of the conductors increases significantly, the fragments of the short-circuit current sharply increase, and the short-circuit strength is small, so the heat that is seen in the conductor cannot be transferred to the excess medium and practically for heating the conductor.

– pitomy opir and heat capacity at 0 about C (I 2 t) add. In case of presence of the automatic reclosure device (AR), the total thermal current of the short circuit must be protected. - In the case of a short-circuit rate up to 1, during the process of heating the conductors under the action of the current, the short-circuit is permissible to be considered adiabatic, and in case of a short-circuit rate of more than 1 s and in case of non-fluid reclosing, the heat output is restored in the middle of nowhere. B before? to t

B before? strum short circuit at a certain moment in time

, A; Vimk - rozrakhunkova trivalist KZ, p. A close assessment of the thermal action stage of a short circuit can also be carried out using an additional thermally equivalent short circuit stage

8.2.2. I

ter.ek, tobto. constant in amplitude (sinusoidal) stream, which in an hour, which is a traditional short circuit, supplies the conductor or electrical apparatus with the same thermal surge as a real short circuit stream in the same hour. ter.ek, tobto. This string of connections with the Joule integral is easy to understand ter.ek, tobto. The Joule integral can be valued approximately as the sum of the integrals of the periodic and aperiodic short-circuit storage current, then.

– pitomy opir and heat capacity at 0 about C ter.ek, tobto. U

ter.ek, tobto. to =

8.2.3. Joule integral (and thermally equivalent short-circuit current) is a complex function of the parameters of energy sources (generators, synchronous compensators, electric motors), configuration of output circuits, position of Hunk's short-circuit point should contain energy, distance from other and other factors.

Therefore, it is recommended that the method of analytical analysis of the Joule integral (thermally equivalent to the short-circuit current) should be based on the peculiarities of the analysis scheme.

8.2.4. In front of the output circuit diagram, fold the equivalent circuit, in which, when expanding the cob value of the periodic warehouse flow of the short circuit (section 5.2.2), synchronous and asynchronous machines will be represented by pointing to the base voltage level or expressions in the leading units for the selection of basic minds by supra-transitional supports and supra-transitional EPCs. Then transform this scheme into the simplest scheme, the type of which lies in the minds of the outgoing minds (divisions 8.2.4 - 8.2.7), and, accordingly, from the simplest scheme, one of the following formulas means Joule integral or thermally equivalent strum short circuit. As the output rotary circuit is of a sufficient nature, all generators and synchronous compensators of the rotary short circuit are removed, then. 8.1 , de W - moment of support, m3. In relation to the current value of the periodic storage flow of any generator (synchronous compensator), the initial short-circuit moment does not reach the nominal flow of two, then it is necessary to transform all energy sources (generators, synchronous and compensators and parts of most remote parts of the electrical power system) must be replaced one equivalent element, the EPC of which is important for constant amplitude, and the inductive support is equal to the equivalent resultant support

, (8.4)

– pitomy opir and heat capacity at 0 about C Vimk - rozrakhunkova trivalist KZ, p. X

From the rozrakhunkovy scheme (div. Fig.).

At what point does the Joule integral follow this formula? ps - the value of the periodic storage current of the short circuit as an equivalent source of energy (system), A;

T

a.ek – equivalent to the constant extinguishing time of the aperiodic storage stream of the short circuit, p.

. (8.5)

Small B before? 8.1. From the rozrakhunkovy scheme (div. Fig. The simplest substitution circuits

; (8.6)

. (8.7)

8.2.5. It is obvious that the rotary circuit is designed to accommodate a number of generators of the same type (synchronous compensators), and the remaining ones exist in the same minds around the short circuit point (all machines and blocks are connected to the ground busbars), and the rotary short circuit is near kim, tobto. Then transform this scheme into the simplest scheme, the type of which lies in the minds of the outgoing minds (divisions 8.2.4 - 8.2.7), and, accordingly, from the simplest scheme, one of the following formulas means Joule integral or thermally equivalent strum short circuit. Since the value of the periodic storage flow of the generator (synchronous compensator) at the initial short-circuit moment exceeds its rated flow two or more times, then the equivalent circuit must also be converted to the simplest circuit in order to replace the equivalent operation , what is the result. g ta EPC E 8.1 , 6.3. g (small)

, (8.8)

– pitomy opir and heat capacity at 0 about C Vimk - rozrakhunkova trivalist KZ, p.), the EPC protection changes over time.

From the rozrakhunkovy scheme (div. Fig. p0g - cob value of the periodic storage flow of the short circuit of the generator (synchronous compensator).

A;

, (8.9)

– pitomy opir and heat capacity at 0 about C Vimk - rozrakhunkova trivalist KZ, p. a.g - constant time of extinguishing of the aperiodic storage current of the short circuit of the generator (synchronous compensator), s;

Joule's transfer integral: 8.2.

p t g - the value of the periodic storage flow of the short circuit of the generator (synchronous compensator) at a certain moment in time, A.

. (8.10)

The values ​​of the Joule input integral for different distances of the short-circuit point from the generator (synchronous compensator), then. B before? 8.1. From the rozrakhunkovy scheme (div. Fig. In various relationships, the current value of the periodic storage flow of the machine at the beginning of the short circuit to the nominal flow can be determined according to the curves in Fig.

; (8.11)

. (8.12)

In this case, the thermally equivalent flow of the short circuit follows the formula

8.2.6. At 8.1 , a.g the value of the Joule integral and the thermally equivalent short circuit strum is permissible using the formula Small g ta EPC Then transform this scheme into the simplest scheme, the type of which lies in the minds of the outgoing minds (divisions 8.2.4 - 8.2.7), and, accordingly, from the simplest scheme, one of the following formulas means Joule integral or thermally equivalent strum short circuit. 8.2. g ta EPC It is obvious that a multi-segment circuit will accommodate different energy sources, and a multi-short circuit will divide the circuit into two independent parts, one of which will contain the energy source, for some short-circuits it will be removed, and the other will be one or the same generator ів (synchronous compensators), which is in the current minds of short circuit points, and for this machine or group of machines the short circuit is close, then the equivalent equivalent circuit may be converted to a double circuit (Fig. Then transform this scheme into the simplest scheme, the type of which lies in the minds of the outgoing minds (divisions 8.2.4 - 8.2.7), and, accordingly, from the simplest scheme, one of the following formulas means Joule integral or thermally equivalent strum short circuit. V .

): VSI JERELALEN ENERGIA, for the Yaki Kz є vіddalenim, I Elehementa, the same Zvyazyu to the point of the KZ, the Slice of the Vygvikhilka, the same

(8.13)

s, and a machine or a group of machines, for which short circuit is close, - it looks like there is another valve with EPC that changes in an hour

The values ​​of the extension integral, when the distance from the short circuit point is determined, can be calculated from the curves. Such curves for synchronous generators with an independent thyristor excitation system are shown in Fig. 8.3.

Small 8.3.

Curves for assigning synchronous generators

with thyristor activation system From the rozrakhunkovy scheme (div. Fig. In quiet weather, if 3 B before? 8.1. From the rozrakhunkovy scheme (div. Fig. a.g >

(8.15)

a.ek, the value of the Joule integral is permissible vikoristuvat viraz B before? 8.1. From the rozrakhunkovy scheme (div. Fig. Well

a.d, then it is permissible to vicorize the formula ter.ek, tobto. The thermally equivalent flow of the short-circuit trace is calculated after formula (8.2), substituting the previously found value before it

8.2.7. before. 8.1 , It is obvious that a multi-arc circuit will accommodate different energy sources, and a multi-arc circuit will divide the circuit into two independent parts, one of which will contain the energy, for some short circuits it will be removed, and the other will be a group of similar elements. rodviguns (synchronous or asynchronous), for any short circuit - close, then the equivalent substitution circuit may also be converted to a two-promenade circuit (Fig. G g ta EPC): all energy sources, for which short-circuits are removed, and the elements that are connected to the short-circuit point, follow the supply unchanged at the amplitude of the equivalent EPC Then transform this scheme into the simplest scheme, the type of which lies in the minds of the outgoing minds (divisions 8.2.4 - 8.2.7), and, accordingly, from the simplest scheme, one of the following formulas means Joule integral or thermally equivalent strum short circuit. with the resulting equivalent support g ta EPC s, and the group of electric motors is equivalent to EPC Then transform this scheme into the simplest scheme, the type of which lies in the minds of the outgoing minds (divisions 8.2.4 - 8.2.7), and, accordingly, from the simplest scheme, one of the following formulas means Joule integral or thermally equivalent strum short circuit. d and equivalent support

bud. Vimk - rozrakhunkova trivalist KZ, p. In this case, the Joule integral is calculated using one of the formulas introduced in section 8.2.6, having previously been replaced in it From the rozrakhunkovy scheme (div. Fig. p0g ta Vimk - rozrakhunkova trivalist KZ, p. a.g. with similar values From the rozrakhunkovy scheme (div. Fig. p0d i 8.4-8.7.

a.d. for an equivalent electric motor, as well as i-linear integrals of an equivalent electric motor. ter.ek, tobto. Depth curves for synchronous and asynchronous electric motors for different bearings of the current value of the periodic storage flow of the equivalent electric motor at the beginning of the short circuit to its nominal flow are shown in Fig. .