Dzherela reactive tightness in electric chains. Reactive tension in the electric line
Electric energy, which is generated by generators of power plants, is characterized by both active and reactive power. The active tension is reduced by electric devices, turning into thermal, mechanical and other types of energy. Reactive pressure characterizes electricity, which is transformed into the energy of electric and magnetic fields. IN electric lines that її elektropryymachi vіdbuvaєtsya process of exchange of energy between electric and magnetic fields. Attachments that take part in this process are called reactive tension jets (IRM). Such attachments can be not only generators of electrical stations, but also synchronous compensators, reactors, capacitors, which can be controlled by the law of regulation for additional special benefits.
The tension of the electrical power system (generators, power lines, transformers, electrical receivers, etc.) Povna tightness S with a sinusoidal form of tension, the struma is tied to the active R that reactive Q tightness S 2 = R 2 + Q 2. With whom total tightness S = UI, active R = UI cosj is reactive Q = UI sinj, de Uі I - fiery meaning sinusoidal voltage and struma; j - cut between the stress vectors and the struma.
At the capacitors cables those other types of electrical control, which are characterized by a small support X C, reactive tension Q = U 2 /X C , which is determined by the applied force U, are created electric fields.
In the inductive elements of the system, for example, in reactors, transformers, electric motor, are created magnetic fields. In which direction is reactive tension Q = I 2 X L strum I and inductive support element X L .
Amnisny strum in an ideal condenser viperedzhaє 90 ate. deg. Same pressure of the condenser Q C = UI sin(-j) = - UI may have a negative sign. And here it seems that the capacitor generates reactive pressure.
Inductive jet in an ideal reactor with a voltage of 90 units. deg. Reactor pressure Q L = UI sinj is a positive sign. And here it seems that the reactor is slowing down the reactive pressure.
It is obvious that the concepts of “generation” and “slowing down” of reactive tension have a lot of intelligence, but it is worth noting that the interplay of imaginary and inductive elements may have a compensating effect QS = QL – QC. The power of the elements is widely used to compensate for reactive pressure, thereby reducing the drop in voltage in the mesh, using electricity. Induce more values of S, P, Q to stop during the changes of the regimes in electric power systems, designed by the choice of electric control. The values of these quantities are taken as independent of the hour, which allows you to significantly ask for a change. In fact, it flows along the Lanziug change strum, Mitteve meaning of which is determined by viraz i \u003d Im sin (wt - j). Under the influence of the strum on the elements of the lancet, the voltage is restored ua = Um cosj sin (wt - j) - warehouse is active and ur = Um sinj sin (wt - j ± p / 2) - warehouse is reactive. Here Um and Im - amplitude sinusoidal voltage that struma. In case of tightness, relieved by active elements electric lansyug, is shown as a function of the hour by the virase pa = iua = UI cosj, and reactive tension, which is reduced (generated) by reactive elements, -qp = iup = ±UI sinj sin2(wt - j). Linear diagrams, which shows the magnitude of the voltage and the struma in the active-inductive lance, as well as the magnitude of the tension induction in Fig. 8.1. The amplitude of the active and reactive tensions, which change according to the sinusoidal law from the subwave frequency (2w), it is possible to set P = UI cosj and Q = UI sinj, then. these are the meanings of tightness, which are coryzed during the rise of the regimen of that choice of possession. When tsimu mittєvі the meaning of "spawned" in the inductive elements and "generated" in єmnіsnih elements reactive tightness at the skin moment, the protractile sign is washed up for an hour, in which case, as it was assigned more, it manifests itself in mutually compensating action.
Literature:
1. Electrical systems. Electric fences / Vєnikov V.A., Glazunov A.A., Zhukov L.A. ta in.; For red. Stroyeva
V.A. - 2nd view., Rev. that dod. M: Vishcha school, 1998.
2. Static compensators for reactive pressure in electrical systems: Per. thematic zb. robitnik
group ІCh-38 SIGRE / For red. Kartasheva I.I. M: Energoatomizdat, 1990.
3. Static nerves of reactive tension in electric strings / Vєnіkov V.A., Zhukov L.A., Kartashev
I.I., Rizhov Yu.P. M: Energy, 1975.
Crim generators, reactive pressure vents can be used and other attachments, installed at substations or at the saving electric power.
Before such extensions, one can see synchronous compensators - machines that are wrapped around, with a salient pole rotor, on which the winding is energized. The synchronous compensator mode is similar to the synchronous motor mode, which works in idle mode.
Baby 5.12
Small 5.12 shows the substitution circuit and the vector diagram of the synchronous compensator, on the basis of which the strum of the synchronous compensator is shown
and also, tightness on yoga grips
S s.c. = Q s.c. = √3U s.c. I s.c. = (5.1)
Viraz (5.1) shows that the value is the sign of the tightness of the synchronous compensator compensator that voltage at the point included in the mesh. Electrodestructive force depends on the size of the struma of the awakening, moreover, the growth of the struma of the awakening is indicative of the increase in e.r.s.
For the struma of arousal, one can take such a value, for which E q = U s.k. In this mode, the pressure of the synchronous compensator Q s.k. = 0. With some increase in the stream, the compensator can see the same reactive pressure Q s.k. > 0. This mode of the synchronous compensator is called self-excitation mode. Change strum zbudzhennya, you can take it off sleep mode, in which E q< U с.к и Q с.к < 0. Поскольку перевод синхронного компенсатора из одного режима в другой, а также изменение его мощности достигается соответствующим изменением тока возбуждения, то управление режимом компенсатора осуществляется плавно, без скачков как при ручном, так и при автоматическом регулировании.
The nominal pressure of the synchronous compensator is indicated for the over-excitation mode, in which the compensator acts as a measure of reactive pressure. In the mode of under-excitation, the compensator relieves reactive tension from the measure. Boundary tightness at which one is manifested
Q s.k (ndv) = - (5.2)
Reactive support of compensators in high-pressure units X d = 1.7-2.0% Rated voltage compensator is taken
Q s.k (ndv) ≈ 
Synchronous compensator, which works in the over-excitation mode, building to increase reactive pressure, which can be seen in the line when the voltage in the line is reduced. Viraz (5.1) shows that the increase will be greater in that case, if with a decrease in the voltage U s.k. Eq. Such an effect can occur with automatic regulation of the compensator damage stream. The special features of synchronous compensators are shown, they are called different positive regulatory effect, allows you to improve the characteristics of the mode of the electric circuit of the system in case of stagnation.
On the little 5.13 shows the scheme of the end yard of the merezha. A battery of static capacitors is switched on on the busbars jet support X to, the tension is showing
vector diagram, induced for the circuit diagram (Figure 8.3) shows that under the injection of the capacitor bank, the reactive tension of the line changes with the constant tension of the tension.
Baby 5.13 Baby 5.14
A battery of capacitors on the side of a synchronous compensator can hardly see reactive pressure. Second dictatorial peculiarity condenser batteries - sharp accumulation of reactive pressure in the form of voltage at the point of inclusion of the battery in the mesh. Formula (5.3) shows that a decrease in the voltage can be reduced to a change in Q k. Also, in the case of a synchronous compensator, a capacitor bank is characterized by a negative regulatory effect. Change the level of the change in the intensity of the battery with a sharp decrease in the voltage, or you can reach a certain positive regulatory effect by changing the X k support. A sharp change in the intensity of the battery can be reached with the so-called boosting of the battery, which is carried out for an additional switch, as if to increase the voltage on the other capacitors. For example, by switching a three-phase battery of static capacitors (div. 8.4), connected behind the circuit, you can increase the voltage of the skin phase of the battery by several times.
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8. JERELA REACTIVE FAULT
8.1. Reactive tension in the electric line
Electric energy, which is generated by generators of power plants, is characterized by both active and reactive power. The active tension is reduced by electric devices, turning into thermal, mechanical and other types of energy. Reactive potency characterizes electricity, which transforms into the energy of electric and magnetic fields. In the electrical system and її electrical receivers, the process of exchanging energy between electric and magnetic fields takes place. Attachments that take part in this process are called reactive tension jets (IRM). Such attachments can be not only generators of electrical stations, but also synchronous compensators, reactors, capacitors, which can be controlled by the law of regulation for additional special benefits.
The tension of the electrical power system (generators, power lines, transformers, electrical receivers, etc.) External tension S with a sinusoidal form of tension and the struma is connected with active P and reactive Q tension with a quadratic fallow S 2 \u003d P 2 + Q 2. When the total tension is S = UI, active P = UI cosj i reactive Q = UI sinj, de U and I - the inflatable value of the sinusoidal voltage and struma; j - cut between the stress vectors and the struma.
In capacitors, cables and other types of electrical control, as it is characterized by an imaginary support X C, reactive pressure Q \u003d U 2 /X C, as it is characterized by an applied voltage U, electric fields are created.
In the inductive elements of the system, for example, in reactors, transformers, electric motors, magnetic fields are created. In this direction, the reactive tension Q = I 2 X L is determined by the strum I and the inductive support of the X L element.
Amnisny strum in an ideal condenser viperedzhaє 90 ate. deg. Then the pressure of the capacitor Q C \u003d UI sin (-j) \u003d -UI can have a negative sign. And here it seems that the capacitor generates reactive pressure.
Inductive jet in an ideal reactor with a voltage of 90 units. deg. Reactor pressure Q L = UI sinj has a positive sign. And here it seems that the reactor is slowing down the reactive pressure.
It is obvious that the concepts of “generation” and “slowing down” of reactive tension have a lot of intelligence, but it is worth noting that the interplay of the imaginary and inductive elements has a compensating effect Q S = Q L – Q C . The power of the elements is widely used to compensate for reactive pressure, thereby reducing the drop in voltage in the mesh, using electricity.
Induce more values of S, P, Q to stop during the changes of the regimes in electric power systems, designed by the choice of electric control. The values of these quantities are taken as independent of the hour, which allows you to significantly ask for a change.
In fact, a change strum flows along the Lanziug, and the meaning of this is determined by the viraz i \u003d I m sin (wt - j). Under the influence of the first struma, the voltage is restored on the elements of the lancet a \u003d U m cosj sin (wt - j) - active warehouse i u p \u003d U m sinj sin (wt - j ± p / 2) - reactive warehouse. Here U m і I m - the amplitude of the sinusoidal voltage and the stream. With this tension, which is reduced by the active elements of the electric lance, it is shown as a function of the hour by the virase p a \u003d iu a \u003d UI cosj, and reactive tension, which is reduced (generated) by reactive elements, -q p \u003d iu p \u003d ± UI sinj sin2 (wt – j). Linear diagrams, which show the magnitude of the voltage and struma in the active-inductive lance, as well as the inductive tension, are shown in Fig. 8.1.
The amplitude of the active and reactive tensions, which change according to the sinusoidal law from the subwave frequency (2w), it is possible to set P = UI cosj and Q = UI sinj, then. these are the meanings of tightness, which are coryzed during the rise of the regimen of that choice of possession. With this mittєvі the meaning of "smooth" in the inductive elements and "generated" in the mnіsnyh elements of reactive tension at the skin moment, the opposite sign may appear for an hour, in which, as it was assigned more, and it manifests itself їх mutually compensating effect.
