JPH0150170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a delayed opening device for an automatic section switch or the like used in a distribution line fault section detection system.

Generally, the switch itself is not intended to release short-circuit currents or overload currents, and when such large currents are flowing through the circuit, if you force the switch to open, the contacts may melt due to arcing, etc. So,
First, a delayed opening operation is required to open the circuit breaker and then open the switch.

Current high-voltage power distribution line fault section detection systems generally employ a timed sequential system as shown in Figure 1. If a ground fault occurs, for example, at point P in the section during normal power transmission, the circuit breaker at the substation CB cuts off,
There will be a power outage after CB. Then, as shown in the time chart of Fig. 2, after a short time delay, the timed progressive control boxes RY ₁ , RY ₂ . . . turn off, opening the automatic section switches DM ₁ , DM ₂ . It turns out. After that, when CB recloses, power is distributed to the first section, and RY ₁ detects this and determines the turn-on time.
Turn on DM ₁ after X ₁ (e.g. 10 seconds) and set the detection time
Time Y ₁ (for example, 5 seconds). When DM ₁ is turned on, power is transmitted to the 1st section, but since no ground fault has occurred in this section, the next automatic section opening/closing will start X ₂ hours after the previous DM ₁ A turns on. The device DM ₂ turns on and transmits power to the first section. In DM _2, time Y ₂ is counted as in DM ₁ , but since there is a ground fault point P in this first section, the circuit breaker CB shuts off again during the detection time Y ₂ ,
At this time, the timed progressive control box RY ₂ is locked. Therefore, the accident section can be detected by measuring the time from when the CB is reclosed to when it is shut off again. The time t in the above example is X ₁ +X ₂ <t<X ₁ +X ₂ +Y ₂ . After this, the circuit breaker CB closes again, but since the time-limited progressive control box _RY2 is locked, power is transmitted only to the first section and the second section, and is disconnected from the second section onward.

As shown in FIG. 3, for example, an electromagnet 11 is used in the automatic division switch DM used in this accident section detection system to drive the movable contact 10 of the switch.
Magnetomotive force to attract 2 and movable iron core 1 after attraction
2 to the fixed core 13, so in order to suppress the heat generation and power consumption of the fixed core 13, a large magnetomotive force is applied when attracting the movable core 12, and a large magnetomotive force is applied when the movable core 12 is attracted. It is a good idea to obtain a small magnetomotive force that is sufficient to maintain the adsorbed state. For this purpose, a closing winding 3 and a closing state holding winding 4 are wound around the fixed iron core 13, and a delay release circuit 5 is provided between the control voltage input terminals 1 and 2 and the windings 3 and 4. Therefore, for the required time (for example, 0.5 seconds) after the control voltage is input, a large current is passed only through the closing winding 3, giving a large magnetomotive force (ampere turns) to attract the movable core 12, and after the attraction, the closing occurs. A small current (applied voltage is the same) is passed through the state holding winding 4 or the series circuit of this and the closing winding 3 to hold the movable core 12 with the minimum magnetomotive force, and the control electrical input disappears. There is a delayed release device that is configured to release the holding current after a predetermined time (for example, 2 seconds) has elapsed, deenergize the movable iron core 12, and open the movable contactor 10. 14 in Figure 3 is an automatic division switch
A transformer that transforms and detects the voltage of the transmission line in the section on the substation side to which the DM is connected; 15 is a transformer that transforms and detects the presence or absence of the secondary voltage of the transformer 14 in the control box RY; Reference numeral 16 clocks the closing time X and detection time Y in the accident zone detection system, and after the closing time This is a control circuit that provides a control voltage. As described above, this control circuit 16 is connected to the control box when the circuit breaker CB is shut off again during the detection time Y.
It is configured to lock the operation of RY and operate so as not to drive the output relay 17 when the circuit is closed again.

Now, in the conventional delay release circuit, as shown in Fig. 4, a full-wave rectifier RF is connected to control voltage input terminals 1 and 2, its secondary side is used as a control power supply, and a closing winding 3 is connected between the control power supply. (a wire with a thick wire diameter is wound several thousand turns to reduce the DC resistance value) and a winding 4 for maintaining the closed state (a wire with a thin wire diameter is wound in tens of thousands of turns to increase the DC resistance value). Connect in series and also between the control power supply a resistor R ₂ and a capacitor C ₂
A smoothing/time constant circuit consisting of a resistor R 1 and a capacitor C ₁ is connected through a reverse current blocking diode D ₂ , and a time constant circuit consisting of a series circuit of a resistor R 1 and a capacitor C ₁ is connected.
A relay 6 is connected to both ends of C ₁ , and the b contact 7 of the relay 6 is connected in parallel with the winding 4 for maintaining the closed state. When the control voltage V _C is input between input terminals 1 and 2, the entire Full-wave rectification is performed by the wave rectifier RF, and the closing winding 3 is excited through the b contact 7 of the auxiliary relay 6, so that the movable iron core 12 of the switch DM is attracted and the movable contact 10 is also closed. then resistance
When the voltage across the capacitor C ₁ of the charging circuit consisting of R ₁ and capacitor C ₁ rises above the operating voltage of the auxiliary relay 6, the relay 6 operates, the b contact 7 opens, and the closing winding 3 and the closing state are maintained. The magnetic winding 4 is excited in series to provide a magnetomotive force that maintains the movable core 12 in its attracted state with a small current value.

To explain the operation of this conventional delay opening circuit, in the case of normal section closing and opening, as shown in Fig. 5, the circuit breaker CB is sent from the control box RY after closing time X.
If the control voltage input V _C is input before the cutoff,
After a short time lag _T1 , the movable contact 10 of the switch DM closes, the auxiliary relay 6 operates at time _T2 as shown in Fig. 5(d), and its b contact 7 opens and operates with a small current. The iron core 12 is held. capacitor
The voltage V ₂ across C ₂ is charged and discharged using the closing winding 3 with low DC resistance, resistor R ₂ and capacitor C ₂ as a closed circuit for T ₂ hours after the control voltage input V _C is input. (Because the control power supply is _a single-phase full-wave rectifier type) is repeated, and the charging current is large, resulting in a _DC waveform that includes large ripples. line 3
Since the current is charged and discharged in a closed circuit including the closed-state holding winding 4, resistor _R2 , and capacitor _C2 , smooth direct current with little ripple is generated. The circuit breaker CB of the substation is closed by closing the automatic sectional switch in the subsequent ground fault section.
When the control voltage V _C becomes zero, the voltage V ₂ across the capacitor C ₂ attenuates with a time constant of C ₂ (R ₂ +r _c +r _h ). (However, r _c is the closing winding 3
(where r _h is the DC resistance of the closed-state holding winding 4) When the voltage across the capacitor C ₁ becomes lower than the open circuit voltage of the auxiliary relay 6, it opens and its contact ₇ closes. The voltage V ₂ is C ₂ (R ₂ +
r _c ), and when the voltage V ₂ becomes less than the voltage that maintains the holding magnetomotive force of the electromagnet 11 of the switch DM, the movable iron core 12 opens and at the same time the movable contact 10 opens. Therefore, the delayed opening time becomes _T3 as shown in FIG. 5b, and the load current I _L due to the closing of the switch DM becomes as shown in FIG. 5e.

Next, in the case of closing the short circuit section, as shown in FIG. 6, when the control voltage V _C is input, the movable contact 10 of the switch DM is closed after a time lag of _T1 .
Since a short circuit current flows at the same time as the power is turned on, the voltage of the power distribution line drops rapidly, and therefore the control voltage V _C also drops rapidly. Then, since auxiliary relay 6 has not yet activated and contact 7 remains closed, the capacitor
The voltage V ₂ across C ₂ discharges with a short time constant of C ₂ (R ₂ + r _c ), and when it drops to a voltage value below the magnetomotive force to maintain the closed state of the electromagnet 11, the movable contactor of the switch DM 10 is open. Since the opening operation time of circuit breakers in substations is set to 0.2 to 2 seconds,
If the opening time _T'5 of the switch DM is about 0.1 seconds, the short circuit current _IS will open the switch DM as shown in FIG. 6e, leading to damage to the switch DM. In addition, the voltage V ₂ across the capacitor C ₂ is charged and discharged in the circuit consisting of the closing winding 3, the resistor R ₂ , and the capacitor C ₂ , resulting in a waveform with large ripples. This affects the voltage at which discharge starts, and therefore the delay opening time.
There is a drawback that T' ₃ fluctuates greatly and if discharge starts from a low voltage, the delayed release time T' ₃ becomes even shorter.

The present invention eliminates such conventional drawbacks, and can secure a delayed opening time so that the switch opens later than the breaking time of the circuit breaker CB even when the short circuit is closed, and moreover, can maintain a constant delayed opening time. It is an object of the present invention to provide a delayed release device that can obtain the following results.

The present invention will be explained below based on the embodiment shown in FIGS. 7 and 8. The overall configuration of the delayed release device is the third one.
Components that are the same as those shown in the figures and that are the same or equivalent between the embodiments and the conventional example shown in FIG. 4 are designated by the same numbers or symbols to avoid duplication of description.

In the delay release circuits shown in FIGS. 7 and 8, the closing winding 3, the closing state holding winding 4, and the backflow blocking diode _D1 are connected in series between the control power supplies, and both windings 3 , 4 is connected in parallel with a smoothing/time constant circuit consisting of a resistor R ₂ and a capacitor C ₂ . Further, in the first embodiment shown in FIG. 7, the b contact 7 of the relay 6 is used as a shorting element for the closing state holding winding 4 and the diode _D1 , and in the second embodiment shown in FIG. 8, a thyristor is used as the shorting element.
This is a non-contact version using T _h .

First, the first embodiment will be described. The normal section closing and delayed opening functions are the same as those of the conventional circuit, but the effect of providing the diode _D1 appears in the short circuit section closing and opening.
That is, as shown in Fig. 9, the movable contact 10 of the switch DM is closed after a short time lag T1 due to the control voltage V _C input between terminals 1 and ₂ , and at the same time as the switch is closed, a short circuit current is generated at the short circuit point. Control voltage for flowing
V _C drops rapidly. At this point, the auxiliary relay 6 is not activated, so the contacts 7 remain closed. Therefore, due to the existence of the reverse blocking diode _D1 , the discharge path of the capacitor _C2 does not go through the contact point ₇ , but instead passes through the resistor R2, the closing winding 3, and the closing state holding winding ₄ . The attenuation of the voltage V ₂ between both ends becomes gentler than in the conventional case.
Therefore, the delay opening time T' ₃ is equivalent to the opening time T ₃ when the normal section is turned on. Since this delayed opening time T' ₃ is longer than the breaking time of the circuit breaker CB in the substation, the short circuit current I _s is opened by the circuit breaker CB as shown in Figure 9 e and f, and then the automatic sectional switch
Since DM will be opened, the switch will no longer release the short circuit current. Also, capacitor
Charging of _C2 occurs in the forward direction of the reverse blocking diode _D1 , and discharging occurs via a high resistance (the resistance value of the winding 4 for maintaining the closed state), so the voltage across the capacitor _C2 is _V2 . Since the DC voltage is close to the peak voltage of the control power supply and the ripple is reduced, the instantaneous value of V ₂ during a power outage (when the control voltage input is erased) is constant, and therefore the delay opening time T′ ₃
This also makes it possible to accurately set the delay opening time relative to the breaking time of the circuit breaker CB.

Next, the second embodiment shown in FIG. 8 will be described. Voltage dividing resistors R ₁ and R ₃ are connected in series between the control power supply via a reverse current blocking diode D ₂ , and the resistor R ₃
Connect smoothing capacitor C ₁ in parallel with resistor R ₃
A differentiation circuit consisting of a capacitor C ₃ and a resistor R ₄ is connected in parallel with the capacitor C ₃ and a resistor R ₄ is connected to one end of the control power supply from the connection point of the capacitor C ₃ and the resistor R 4, that is, in parallel with the resistor R ₄ . Connect diode D ₃ ,
Further, the connection point is connected to the gate of the thyristor _Th via the current limiting resistor R ₅ and the Zena diode ZD. Connect an operation stabilizing resistor _R6 between the gate and cathode of the thyristor T _h . When terminals 1 and 2 control voltage V _C is input, the voltage of the single-phase full-wave rectified control power supply causes diode D ₂ and suppression resistor R ₁
Capacitor _C1 is charged through. On the other hand, capacitor C ₃ is charged by the voltage across capacitor C ₁ through a parallel circuit of resistor R ₄ , resistor R ₅ , Zena diode ZD, and resistor R ₆ . At this time, when the terminal voltage of the resistor R ₄ exceeds the zener voltage of the zener diode ZD, current flows through the zener diode ZD to the closing winding 3 due to conduction of the thyristor T _h . Further, the smoothing capacitor _C4 is charged through the suppressing resistor _R7 , discharged through the making winding 3, and smoothing the current flowing through the making winding 3, and the voltage between the anode and cathode of the thyristor _Th increases every half cycle. Increase the time to zero.
The capacitance of the capacitor C ₃ is selected so that the gate current of the thyristor T _h disappears after a sufficient period of time after the electromagnet 11 is turned on by the closing magnetomotive force of the closing winding 3 . Therefore, when the gate current disappears and the voltage applied between the anode and cathode becomes zero, the thyristor T _h automatically changes to a non-conducting state. That is, since the control power source is a single-phase full-wave rectified voltage, when the voltage becomes zero, it becomes less than the holding current of the thyristor, and the thyristor T _h becomes non-conductive within half a cycle after the gate current disappears. On the other hand, capacitor C ₂ is charged instantaneously through resistor R ₂ at the same time as voltage is applied between terminals 1 and 2.
Provision is made to delay opening of the electromagnet 11 in the event of a power outage. When the normal section is closed, current flows through the closing winding 3 and the closing state holding winding 4 due to non-conduction of the thyristor T _h , and the movable iron core 12 is held with a small holding current, which is the same as in the first embodiment. . When the short-circuit section is turned on, the charge of capacitor C ₂ is transferred to resistor R ₂ , both windings 3,
4 is also similar to the first embodiment.

As described above, in the present invention, a DC voltage is generated by inputting a control voltage in a delayed opening device for a switch that drives a movable contact by an electromagnet in which a closing winding and a closing state maintenance winding are wound around a fixed core. A closing winding, a closing winding, and a backflow blocking diode of the electromagnet are connected in series between the control power supply, and a resistor and a capacitor are connected in parallel to the closing winding and closing state maintaining winding. A smoothing and time constant circuit constituted by the above is connected, and a shorting element is connected in parallel to the closed state holding winding and the reverse current blocking diode, and the shorting element is connected within a certain period of time from the time of inputting the control voltage input. A delay release device is constructed by providing a delay control circuit that maintains the short-circuit state, and achieves the following effects.

(1) When the short-circuit section is closed, the delayed opening time can be made longer than the cut-off time of the circuit breaker at the substation, just as when the normal section is closed, and the switch, which does not have the function of interrupting the short-circuit current, fails to open the short-circuit section and is damaged. This can be prevented with a simple configuration.

(2) Since the discharge of the capacitor for delay opening is performed through a high resistance, ripples in the voltage across the capacitor are reduced, and fluctuations in the delay opening time are small and constant.

[Brief explanation of drawings]

Fig. 1 is a power distribution system diagram showing a fault section detection system to which the delayed release device of the present invention is applied, Fig. 2 is an explanatory diagram showing its operation, and Fig. 3 is a circuit diagram showing the overall configuration of the device of the present invention. , FIG. 4 is a circuit diagram showing a conventional delay release circuit, and FIG. 5 is a waveform diagram showing waveforms of various parts in the conventional circuit when the normal section is closed.
FIG. 6 is a waveform diagram showing the waveforms of various parts when the short-circuit section is turned on in the conventional circuit, FIGS. 7 and 8 are circuit diagrams showing the first and second embodiments of the present invention, respectively, and FIG. 9 is the circuit diagram of the present invention. FIG. 3 is a waveform diagram showing waveforms of various parts in the circuit.

Claims (1)

[Claims] 1. Control for generating a DC voltage by inputting a control voltage in a delay opening device for a switch that drives a movable contact by an electromagnet having a closing winding and a closing state maintenance winding attached to a fixed core. A closing winding, a closing winding for maintaining the closing state, and a reverse current blocking diode of the electromagnet are connected in series between the power supplies, and a resistor and a capacitor are connected in parallel to the closing winding and the closing state maintaining winding. Connect the smoothing and time constant circuit to be
A delay control circuit is provided in which a shorting element is connected in parallel to the closed state holding winding and the reverse current blocking diode, and the shorting element is held in the shorted state for a certain period of time from the time of inputting the control voltage input. Delayed opening device for switchgear. 2. The delay opening device for a switch according to claim 1, wherein the delay control circuit is composed of a relay that operates with a delay, and the shorting element is a contact point of the relay. 3. The shorting element is a thyristor, the ignition circuit for the thyristor that performs a delayed return operation is configured as a delay control circuit, and the control power source is a full-wave rectified waveform voltage having zero voltage in every half wave. A delayed opening device for a switch according to claim 1.