SU652648A1 - Adjustable capacitor unit - Google Patents

Description

The invention relates to the field of power converter technology and can be widely used for longitudinal compensation circuits in high voltage networks, where voltage stabilization is required under fast alternating load.

In known longitudinal adjustable compensating installations in series with a capacitor, an adjustable choke is turned on, the inductance of which is varied by biasing 1. The disadvantage of such installations is greater inertia, significant losses of active power in the choke, the possibility of waving caused by and inductance.

In a known adjustable condensing unit to regulate the equivalent capacitance of a static capacitor, parallel fully connected valves 2 are connected in parallel to the capacitor. In such a regulator, fully controlled valves are used to control the equivalent capacitance, which are released to a limited power and the ear

time, not practical applications. The voltage on the static capacitor has a pronounced non-sinusoidal form with long dips down to zero, which indicates a high specific gravity of the highest harmonic voltages in the composition of the entire curve. This circumstance adversely affects the operation of the capacitor and shortens the service life.

Closest to the present invention is an adjustable capacitor unit comprising a capacitor, shunted by anti-parallel-connected control valves, in series with which a diode is connected, and the control valves themselves are shunted by a transformer winding, in series with which capacitors 3 are connected.

A disadvantage of this device is the presence of an artificial switching circuit containing a transformer winding and capacitors, which complicates the circuit and reduces the efficiency of the regulator, as well as the non-sinusoidal voltage waveform on the capacitor of the regulator with long-term failure to zero, which sharply shortens the service life of the condensers. , -. The purpose of the invention is to simplify the circuit and improve the sinusoid of the voltage curve on a static capacitor.

This goal is achieved by the fact that the arrangement is equipped with additional meetings W nfpWe tf BKjfto eftHbiMH W shventilili, one conclusions of which are connected to the second output of the capacitor battery, and the second connected to the second conclusions of the first counter-parallel controlled LH.

FIG. I shows the principle scheme of the Mugul torus of the value of the equivalent capacitance of a static capacitor (single-phase version); in fig. 2a, b, c, d shows time diagrams.

The installation contains controllable valves (thyristors) 1-4 and a capacitor 5. Controlled valves (thyristors) 1 and 4 are connected anti-parallel and parallel to the chain of capacitor 5 and anti-parallel connected controlled valves (thyristors) 2 and 3. The value The equivalent capacitance of the capacitor 5 is controlled by thyristors 1,2, 3, 4, which change the duration of the current flow through the capacitor 5 ..,

The installation works as follows.

Let the voltage of the capacitor 5 to the moment of time t (it had the polarity indicated in Fig. I in brackets. At the moment of time tj (see Fig. 2) a control pulse is applied to the thyristor 3 and a current i of the phase i begins to flow through the capacitor 5 (see Fig. 2c), the polarity of the voltage on the capacitor 5 indicated in Fig. 1, without brackets, remains unchanged until time t (see Fig. 26). At time tj the thyristor 4 turns on and the thyristor 3 turns on using a capacitor 5.

From the moment tz to U, the current i flows through the thyristor 4 (see Fig. 2d). At time ts, the phase current changes direction and the control pulse turns on the thyristor 1, which conducts the TOKi phase until (4) (see Fig. 2d): -

At time 14, the thyristor 2n current i turns on and the phase flows through the capacitor 5, recharging it from, + IJc to –Uc (see Fig. 26) with the polarity indicated in Fig. 1 in-brackets. The recharge current and the condensate flow through the capacitor 5 until the time ts (see Fig. 2c).

At the same time t1. The thyristor 1 is switched off with pMYI1GGI1G) of coPl neator 5, the polarity of which is indicated in FIG. 1 without brackets. At the moment of Time

ts turns on the thyristor 1 again and the phase current flows through it until time tg. Subsequently, the cycle of operation of the regulator is repeated.

From the above description of the regulator circuit, it can be seen that the capacitor 5, besides its main purpose, performs the function of the switching capacitor. For switching off, the time of thyristors 1, 2, 3, 4 is controlled by the controller control system by phase current. Thus, by varying the switching on time of the thyristors 1, 2, 3, 4, the duration of the current flow through the capacitor 5 is regulated and, therefore, the magnitude of the voltage on the capacitor, i.e., its equivalent capacitance. The diagram of operation of the regulator of the value of equivalent capacitance is considered before the mode of the generator of sinusoidal current. Thus, the device allows to increase the service life of the capacitors of the controller due to the improved shape of the voltage curve on them. In addition, the regulator circuit is simplified by eliminating the artificial switching of the transformer and capacitors from the circuit. In the proposed device, the role of a switching capacitor is performed by a static capacitor 5, the capacitance of which is adjustable.

Claims (3)

1. Zhezheleiko IV. Reactive MOHU10CTH compensation in electrical networks with nominal loads. The magazine "Electricity, about 5, 1975. 2..Avtorskoe certificate of the USSR .v 216824, cl. H 023 3/18, 1966. 3..Avtorskoe certificate of the USSR., 235875/07. cl. H 023 3/18, 1976. 3/2 G Vr. / 1 OU ®   / .Uit d, h, e /, iV 1 Cg  t wt i.