JPS5970126A - Stationary protecting relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a static protective relay in which a detection input is always present and outputs an output when a predetermined level is exceeded in the event of an abnormality.

A typical protective relay of this type is an overcurrent relay, which has a detection input corresponding to the load current at all times, and when an abnormality occurs in the system, the detection input exceeds a predetermined level and an output is produced.

By the way, static protection relays require a control power source in addition to the detection input, and the control power source is often used while the detection input is being applied. When the control power supply is important, the reference voltage drops transiently, and there is a period in which the detection input becomes higher than the reference voltage even though it is at a normal value, and the protective relay may operate unnecessarily.

In order to solve this problem, conventionally, a temporary locking signal circuit was installed when the power was turned on and when the power was turned off, and the final output as a relay i*D was temporarily disabled. The lock is designed to prevent unnecessary operating noise from the relay. -f
An example of: is shown in FIG.

In FIG. 1, / is a rectifier that performs full rectification and smoothing of the detection input, and λ is a constant voltage circuit that stabilizes the control power supply voltage to obtain a constant voltage of 1I-1. ? is a reference voltage setting section, G is a comparator circuit that compares the output voltage v1 of the rectifying section/proportional to the detection input with the reference voltage vr, and S is a locking signal generation circuit that generates a locking signal when the power is turned on.

t is a locking signal generation circuit that generates a locking signal when the power is cut off; 7 and 7 are inverters that invert the levels of the output signals of the signal generation circuits 1 and 2; An AND circuit receives an output at its input terminal, 10 is a relay drive circuit operated by the output of this AND circuit 9, and // is an auxiliary relay.

Figure 2 (a) (h) (
cl (cl) will be explained with full reference. Constant voltage circuit! The output of is generally smoothed by a capacitor, so it rises gradually from the time the power is turned on, as shown in Figure 2 (al). This shows the case where the voltage is being output.Also, the reference voltage vrl
-j: Foot voltage output Since the full voltage output is obtained, Figure 2 (1)
As shown in , the rise of 7 is also gradual in 9.

On the other hand, since the detection input exists before the 'wL power is turned on, Vl>vr holds true when the power is turned on, and an output is generated at the comparator circuit≠. If the operation of the comparator circuit l is considerably faster than the rise of the constant voltage output, the output of the comparator circuit
As shown in Figure (c), the voltage rises at approximately the same slope as the rise of the foot voltage output, and drops from the point where vl<vr.

Therefore, if the constant detection input is close to the reference level, there will be a period where the output of the comparison circuit is equal to or higher than the operating level u1 of the relay drive circuit 10, as shown in FIG. 2(C), and the auxiliary relay/ / is energized and a relay output is produced as shown in the second [kl (dl).In other words, an unnecessary operation is performed.

On the other hand, when the 'IT source is shut off, Figure 2 (a) (b) (c
Each voltage changes as shown on the right side of l (d),
After all, there is a period in which ■1>vr is established and the output of the comparison circuit ≠ exceeds the 01 operation level 11 of the relay drive 1 circuit 10. At this point, if power is being supplied to the relay drive circuit io from the constant voltage circuit 1, a control power supply πye sufficient to drive the relay //f remains, and an unnecessary output is generated.

Such a problem can be solved by using a circuit configuration as shown in FIG. 1 because the relay output is temporarily locked when the power is turned on or off.

However, although unnecessary output is eliminated when the N-source is cut off, a new problem arises. In other words, it is necessary to add a circuit to lock the relay output f when the % current TJ is high, which not only complicates the circuit configuration and increases costs, but also causes the relay to malfunction due to the additional circuit's operation. Reliability decreases. Luxurious. When the main circuit is simple, the additional circuits occupy a large amount of space, which not only poses a cost problem but also poses a major constraint on miniaturization. Furthermore, when the power is turned on, there is a lock period that is unnecessary for the relay's original function, which reduces the V and Ui functions.

The present invention has been made to solve the above problems, and a series circuit of a variable resistor and an adjustment resistor for establishing a reference voltage is connected between the (+) and (-) output terminals. By selecting the value of the adjustment resistor to set the resistance sharing ratio, the Flr required ratio can be set, and by setting the potential at the connection point of both resistors as the reference (base potential (zero point) of the voltage, t) is unnecessary when controlling the power supply voltage. DESCRIPTION OF THE PREFERRED EMBODIMENTS An object of the present invention is to provide a static protective relay 1 which can prevent operation, has a simple configuration of an additional circuit, and has high reliability.

Figures 8 to 5 show one embodiment of the present invention.
1 is a rectifier that rectifies and smoothes the detection input, n is a voltage source that stabilizes the control power supply voltage, and 2 is a source type constant voltage circuit (-) that is a bipolar DC constant voltage. The power is a reference voltage Vrt- The variable resistor to be set is -2" F!, R'i. Both resistors for paper adjustment n9.24M are connected to the inner row, and are connected between the output terminals (10) and (-) of the constant voltage circuit n. The intermediate point of 1 is connected to the terminal (0).Adjusting resistor 2 is connected so that the sharing ratio of both bending forces and Yuhiro becomes the required ratio.
Select the value of

koS is the rectifier corresponding to the detection input, the output voltage of 2/■1
and a reference voltage Vrg), a differential voltage detecting section for detecting the differential voltage, and an integrating circuit for integrating the output of the differential voltage detecting section.
is an operation level setting section that outputs an output when the output of this integrating circuit, 2B, reaches a certain level, and is composed of passive elements such as Zener diodes and varistors that are not affected by the control power supply voltage.

29 is an auxiliary relay, which is operated by the output of an operation level setting section 27, and an auxiliary relay.

As shown in FIG. 4, the integrator circuit includes an operational amplifier op,
The feedback circuit is composed of a capacitor C1 and an input resistor B1, and the output of the differential voltage detection circuit t3 is connected to the (-) input terminal of the amplifier OP via a resistor R8. The end is connected to the connection point of the double bending force of 1.2 hiro, that is, the zero point.

The constant voltage circuit n includes Zener diodes ZD, ZTJ, resistor RI + capacitor CI as shown in FIG.
*Am is made by Cj. The output voltage of the constant voltage circuit n is supplied to the integrating circuit J and the relay drive circuit 28 as their power supply voltage.

Next, the operation is shown in Figure 6 (a) (b) ((ri (ti)?
I will explain while referring to it. Constant voltage circuit without trench, 22 terminals (+) - (o), (o) by adjusting resistor
- Adjust the burden ratio between (-). In this case, when the power is turned on, the voltage between 1-1- Select the value of

By adjusting in this way, 1, for example, the burden between (+) - (0) 'it Rph (o) - (-1)
If the value of the resistance J is selected so that J' p /RB=10/8 when n.

(→-(0) until the voltage between it reaches a predetermined constant voltage (
+) - (0) voltage Ep and (0) - (-) m-1
The voltage 4 of Rp4. = rises at a ratio of tO/8. When voltage Kp reaches a predetermined constant voltage, voltage Bp becomes constant, and voltage En further increases until it reaches a predetermined constant voltage (61st
jN(a)).

The reference voltage vr is obtained by dividing the voltage by dividing the voltage.

8. Start-up is fast as shown in Figure 1 (b)! ：J1 detection input is 111"-%rEV1 is crossed; 6i
Since tit (W 2 a(b) J), the voltage E between (+) and (-) (Fig. 6, 1(c)) at the point where this Vi-Vr becomes is smaller than before. The relay 2YlIi is kept in the deenergized state when the step-determined operation is less than or equal to the level λ.In other words, unnecessary operation is prevented.

On the other hand, when tracing the 'ijf source, Vi = "r
(!: l If the value of the resistor 217 is selected so that the voltage between (+J and -) at the time of the operation is slightly smaller than the set operating level, unpleasant operation will not occur.Resistance, 2hiro If the value of , , , , t, sth, , q, is equal to 1, unnecessary operations can be prevented when the power source is -J1 if it deviates from the Q value by a small amount.

In addition, in the embodiment n11, the reference voltage is (10) −(of
(0) −(−
) may be used, in which case the adjustment resistor,
2Z is connected between (+)=(0).

As described above, according to the present invention, the variable resistor for setting the reference 1 voltage is connected to one side of the constant voltage circuit of the C+), (-) type constant voltage circuit, and the variable resistor for setting the reference 1 voltage is connected to the other side, respectively. , By selecting the adjustment resistor (if), the sharing ratio of the double-turning resistor is set to the required ratio, so that the reference voltage changes suddenly when the control power is turned on and off, and the output voltage of the integrating circuit changes at the time of Vi w■r. is below the set operation level, and unnecessary operations can be reliably prevented.Furthermore, since the subdivision circuit only requires connecting one adjusting resistor to the output end of the constant voltage circuit, it is much simpler and has a lower It can be manufactured at low cost and can be easily miniaturized.In addition, since the configuration of the subdivided circuits other than the main circuit is extremely simple, there is no risk of lowering reliability, and it is suitable for protection that requires high reliability. This is beneficial for network Tu devices.

Furthermore, between Rock JQ1'? ! : Since it is not installed, the function of the new city equipment can also be demonstrated in Sengen Nage town and it can be used to ensure the safe operation of the @1 system.

[Brief explanation of the drawing]

-(r11
Block I\11 2nd is + (,,) (ts(
c) (, i) explains the unnecessary operation at the time of opening and closing the thunder garlic. A block diagram showing the example. Figure 4 shows the circuit configuration of the integrating circuit in the example
FIG. 5 shows a circuit diagram of the constant voltage circuit in the same embodiment.
nZcll, 210+ Ig+ (a) (b) (c
) (+t) is 6% operation Light E';z+ is 21 /-
1°, 2 no... Rectifier section 1.22... Foot pressure circuit, sword... Variable resistance. J...H1~Adjustment resistance, Noj...Difference 1F pressure detection part,
26...Integrator circuit, Core...1IIIJ level setting section, λg...Relay drive circuit. Kota... Auxiliary relay.

Claims (1)

[Claims] (1) A rectifier that rectifies and smoothes the detection input, a two-power supply type constant voltage circuit that stabilizes the control power supply voltage and obtains a free current constant voltage of (+1, (-)), and one of the constant voltage circuits. The resistance value is selected so that the ratio of the reference voltage setting variable resistor connected between the output terminals of the polarity and the total resistance value of this variable resistor becomes a J'5r constant ratio, and the constant voltage circuit is An adjusting resistor connected between the output terminals of the other polarity, an integrating circuit that detects the voltage difference between the output voltage of the rectifying section and the reference voltage, and integrates this voltage difference, and the output of this integrating circuit is set at a constant level. It is comprised of an operation level setting section that outputs an output to that effect when the operation level setting section reaches the level, a relay drive circuit that is operated by the output of this operation level setting section, and an auxiliary relay that is energized by the output of this relay drive circuit. Static protective relay.