SU352601A1 - Discharge device for protesting high-voltage direct current units against overloading - Google Patents

Description

The present invention relates to the field of electrical engineering, in particular, to devices for overvoltage protection of DC converters.

For protection of high voltage direct current installations, arresters are usually used, the operation of which leads to the shutdown of the protected installation or its part, since modern arresters with spark arrays and spins with a rotating arc are not able to extinguish the accompanying current that does not pass through zero .

Known dischargers containing a series-connected spark gap with a stretching arc and a non-linear resistor do not allow the discharger to be protected from destruction when a long operating current flows through it.

The purpose of the invention is to protect the glitter from destruction when a long operating current flows through it,

This is achieved by the fact that a spark gap with a stretching arc and a nonlinear resistor are shunted by a spark gap with a rotating arc and with a successively formed chain included with one s.oron an additional gap with a rotating arc, and on the other - a current-limiting resistor, which can be made non-linear; in parallel with the current-limiting resistor, an inductor may be included, either made saturable or unsaturated; sequentially with a spark gap in the shunt branch, an additional spark gap with a rotating arc can be switched on, and the point of junction of the gaps is connected to the point

5 connect resistors in the other branch of a linear communication resistor.

FIG. 1. given the general scheme of the discharge; in fig. 2 is a diagram of a ramp in which a linear resistor is connected in series with the spark gap in the shunt branch; in fig. 3 is a diagram of the discharge in which the current-limiting parallel

25 resistor included inductor; in fig. 4 is an arrester circuit in which, in parallel with the current-limiting resistor, an additional spark gap is inserted from the surge mask, in which a linear resistor is connected in the shunt circuit between the spark gap and the connection point of the linear communication resistor.

The proposed arrester contains a spark gap 1 with a stretching arc, a nonlinear resistor 2 connected in series with the spark gap 1, a spark spark 3 with a rotating arc, connected in parallel with the spark gap 1 and the resistor 2, a spark gap 4 with a rotating arc and resistor 5. A resistor 6 can be connected in series with the spark gap 3 (Fig. 2). In parallel with the resistor 5 (Fig. 3.), the inductance 7 can be turned on. Parallel to the resistor 5 (Fig. 4) the spark gap 8 can be turned on.

A high-resistance resistor 9 is connected between the junction point of the two spark-gaps of the shunt branch (Fig. 4 and Fig. 5) and the junction point of the nonlinear eesistor 2 and the current-limiting resistor 5.

The proposed arrester provides protection for the converter plant in two current flow modes after the arrester trips: a) co1: - yes, the protected part of the converter remains in operation. And the current through the 30th row is determined by the voltage on the protected part of the converter plant and the internal resistance -. em discharge. This current is an accompanying current in such an understanding 35 as is customary for AC arresters; b) when the protected part of the converter plant is de-energized at the time of the triggering of the arrester and the working current of the transfer line B can flow through the arrester Q, the value of which practically does not depend on the discharge resistance.

At the moment when the overvoltage on the protected installation (part of the converter installation) comes to the value: Up Up, regardless of mode a or b, which follows after triggering the arrester, at the same time spark gaps trigger - 4 s rotating and with stretching arc (Fig. 1).

; The operation of gap 3 is excluded, since Up Up,.

The capacitance of the protected object is discharged through the nonlinear resistor 2 and the linear resistor 5.

During the time of discharge of the capacitance of the protected object, the voltage Uj on the gap 3 is 0 and Up 3pR.

The value of resistor 5 must be chosen so that), i.e. the false positive of span 3 should be excluded.65

After the firing of gaps 4 and 1, the operation of the glitter depends on the mode a or b and the duration. overvoltages.

In mode a, the discharge voltage rapidly decreases to the nominal value UH. The tracking current is determined primarily by the non-voltage of non-linear resistor 2 at tTc.

After a certain period of time (1 ms), the reverse voltage 1) 2 develops at intervals with a stretching arc, and the instantaneous value of the accompanying current ic. gradually decreases to zero, the arc in interval 1 goes out and the discharge returns to the normal state.

. Spark gap 3 in this case does not work, since the total voltage of voltage is across gap 1 and on resistor 2 T1. + U ,. ()

p gt / p p s

n RZ

in the mode, the operating current of the transmission current flows through the discharge voltage and a non-linear resistor 2 creates a voltage drop and (). After a period of time (1 ms), at intervals of 1 with a stretching arc, the reverse voltage 1) 2c develops. However, in contrast to mode a, as a result, the current through the arrester and, therefore, the voltage drop across the resistor 6 practically cannot change.

. When the total voltage drop across the resistor 2 and the spark gap 1 reaches the average discharge voltage of the gap 3 Pcs (,) +, -Upo, the spark gap 3 triggers and the arc from gap 1 and the nonlinear resistor 2 jumps to gap 3 and linear resistor 6.

The impedance on the discharge at the moment of arc transfer can be set arbitrarily within Up + 10% by selecting the values of R and tlp.,. Line resistors 5 and 6 and gaps 4 and 3 must be designed for throughput determined by J values. After the time expires, the shunt device is activated and de-energizes the de-energizer. J

Claims (8)

The circuit of FIG. 5 differs from the circuit in FIG. 1 in that the non-linear resistor is divided into two parts (2 and 5) and one 6 is used instead of two linear resistors. Non-linear resistor 5 is shunted by a spark gap 8 with a rotating arc. A high-impedance linear resistor 9 connects both branches of the arrester. In this scheme, after the operation of the gap 3, the gap 8 immediately follows the voltage drop on the resistor 9. wearing 11p | and, is comparatively small (1.3-2). In order to increase the bandwidth of the arrester or eliminate the voltage drop across it, the circuit of FIG. 4, different from that of FIG. 5 in that there is no linear resistor b in it. The circuit in FIG. 3 can be used in cases where the duration of the overvoltages is longer than the arc stretching time in the intervals of the stretching arc. The capacity of these gaps is sufficient to pass a charge associated with overvoltage and under the conditions of protection an increase in the total value of the current-limiting resistor of the discharge is allowed. For such a discharge, the degree of detuning between the operation voltage between 1 and 3 and the value of the resistor 5 must be increased compared with those in previous circuits. The inductance can be either saturation or non-desaturating, depending on the specified technical requirements for the discharge. During the overvoltage period, the presence of inductance 7 does not significantly affect the current through the arrester and the current mainly flows through the resistor 5. Stretching the arc in interval 1 during the overvoltage should not lead to the interruption of interval 3, since the voltage drop across resistor 5 is of the appropriate value. The arc reversal occurs only when the operating current of the transfer current (mode b), which is closed through the inductance, is set in the discharge unit, and, therefore, the voltage drop on the resistor 2 will additionally increase by the required value. Claim 1. Spark for protection against overvoltages of high voltage electrical installations of direct current, comprising a series-connected spark gap with a stretching arc and a non-linear resistor, characterized in that, in order to protect the discharger from destruction during long-term flow through it operating current, the indicated gap and the resistor are shunted by a spark gap with a rotating arc and with a successively formed chain included on one side an additional gap with a rotating ugoy, and on the other - limiting resistor. 2. Distribution according to claim 1, characterized in that the current-limiting resistor is made linear, and the linear resistor is connected in series with the spark gap in the shunt branch. 3. Razr Dnik on PP. 1 and 2, characterized in that, in order to prevent false triggering of the gap in the shunt branch, the inductor is switched on in parallel with the current-limiting linear resistor. 4. Razr Dnik on PP. 1 and 3, in that the inductor is made saturable, 5. Parsed bottom popp. 1 and 3, characterized in that the inductor is unsaturated, 6. Distribution according to claim 1, characterized in that the current-limiting resistor is non-linear. 7. Razr Dnik on PP. 1 and 6, in order to facilitate the operation of the arrester, an additional spark-gap with a rotating arc is connected in series with the spark gap in the shunt branch, and the gap junction point is connected to the connection point of the resistors in another branch by a linear communication resistor, 8. Razr Dnik on PP. 1.6 and 7, that is, in order to limit the current, a linear resistor is connected in the shunt branch between the first spark gap and the connection point of the linear communication resistor. 1 FIG. 2 srig.Z "Ko LO vU, / u F1 / g4 ML I G V 5