JPS59122312A - 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 protection relay in which a detection input is always present and outputs a protection output when a predetermined level is exceeded in an abnormal situation.

A typical protection 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 a protective output is issued.

By the way, static protective relays require a control power source in addition to the detection input, and the control power source is often turned on and off while the detection input is being applied. When the control power supply is important, the reference voltage drops transiently, and even though the production input is at a normal value, there is a period when the pressure is greater than the reference voltage, which may cause the protective relay to operate unnecessarily. Money.

This point will be explained with reference to FIGS. 1 and 2. 1st
In the figure, 1 is a rectifier circuit that rectifies the detection input, 2 is a reference voltage setting section, and 3 is a rectified output voltage v corresponding to the detection input.
1 and the reference voltage Vr, an integrating circuit which inputs the difference voltage V4;
is a seven-bell detection circuit that analyzes the level of the output voltage vI of this integrating circuit 3, 5 is a relay drive circuit, 6 is an output relay, 7
is a constant voltage circuit that constantizes the control power supply voltage VD, and the output voltage vc of this constant voltage circuit 7 is supplied to the reference voltage setting section 2, the integration circuit 3, and the level detection circuit 4. However, the control power supply voltage is directly supplied to the relay drive circuit 5. This is to reduce the capacity of the constant voltage circuit and thereby downsize it.

In the mining relay with the above configuration, when the control power supply is turned off, the power supply voltage of the relay drive circuit 5 instantly becomes zero, so even if the output of the level detection circuit 4 is transient, the output relay 5 will operate. However, when the control power is turned on,
As the control power supply voltage VD rapidly rises, the output voltage of the constant voltage circuit 7 increases. will rise later than voltage VD due to capacitors etc.
Even if the output of the level detection circuit 4 is transiently output during this transition, the output relay 6 will be driven, resulting in so-called unnecessary operation.

For example, if the control power supply voltage VD is applied while the voltage v1 corresponding to the detection input is always present, the control power supply voltage VD rises rapidly as shown in FIG.
The rise of the output voltage v0 is delayed due to the capacitor and the like.

Therefore, the reference voltage Tr also rises with a delay like the voltage v0.

On the other hand, the rectified output voltage v1 always exists, and as a result, the difference voltage V between the reference voltage Vr and the rectified output voltage v1
IllFi system #When the power is turned on, it is transient (→,
The output voltage vL of the integral (b) path 3 is the detection level of the level detection circuit 4 as shown in FIG. It started to exceed 1,
Output voltage VR is generated in level detection circuit 4, and output relay 6 is driven by relay drive circuit 5. In other words, the protection relay becomes unnecessary.

The present invention has been made to eliminate the above-mentioned drawbacks, and includes a circuit that differentiates the output voltage of the constant voltage circuit, and the output is directed in the direction of increasing the detection level of the level detection circuit, that is, in the direction of suppressing the operation. By adding the control power
An object of the present invention is to provide a static protective relay that can reliably prevent unnecessary operations when the power is turned on with a simple circuit configuration.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 3 shows an embodiment of the present invention, in which a constant voltage circuit 7
A differentiating circuit 8 is provided to differentiate the output voltage Vc of the output voltage v1. The rectified output voltage v1. It is made to match with the reference voltage vr. In other words, we expect the same operation as when the detection level of the level detection circuit 4 is temporarily raised when the control power supply is turned on.
This applies suppression and avoids unnecessary operations when the control power is turned on.

Note that the other configurations are the same as those of the conventional device (FIG. 1), and the same components are designated by the same reference numerals and their explanations will be omitted.

Next, the operation will be explained with reference to FIG.

When the voltage vD of the control power supply rises while the rectified output voltage v1 is present, the output voltage v0 of the constant voltage circuit 7 rises slowly, and the reference voltage Vr also rises at a similar rate of rise. At this time, the differentiating circuit 8 has a voltage V1. which becomes approximately constant during the rising process as shown in FIG. occurs.

Since this voltage Vt is compared with the rectified output voltage Vi and the reference acid pressure 1, the differential voltage VB is as shown in FIG.
+) and the output voltage of the integrating circuit 3 v1. is zero, so the output voltage vR of the level detection circuit 4 is also zero, and the output relay 6 is maintained in an inoperative state. That is, unnecessary operations are prevented when the control power is turned on.

FIG. 5 shows another embodiment of the present invention, in which the output voltage of the differentiating circuit 8 is added to the reference voltage Vr, and the sum is The voltage is used as the comparison level voltage of the level detection circuit 4, and its operation and effect are the same as those of the previous embodiment.

As described above, according to the present invention, the output voltage of the circuit for constant voltage rolling of the control power supply is differentiated, and the output is made to act in the direction of increasing the detection level of the level detection circuit. Suppression is now applied when "on", and unnecessary operations can be prevented. Moreover, the circuit configuration 1 is quite simple since it only requires the addition of a differentiating circuit, and by appropriately adjusting its output voltage, it can cope with any rectified output voltage v1. In addition, the differential output voltage is output only during the transient period when the output voltage of the constant voltage circuit changes, so as soon as the transient phenomenon ends when the power is turned on, normal operation is possible and the protection function can be fully demonstrated. . Furthermore, the protection function is not activated immediately after the control power is turned on, even if the sensitivity is reduced, because it is not a lock system that temporarily stops the retaining operation when the power is turned on, but a system that suppresses the operation when the power is turned on. have.

[Brief explanation of drawings]

Figures 1 and 2 are a block diagram and operation explanation diagram showing an example of a conventional static protective relay, Figure 3 is a block diagram showing an embodiment of the present invention, and Figure 4 is an explanation of the operation of the same embodiment. figure,
FIG. 5 is a block diagram showing another embodiment of the present invention. ] - Rectifier circuit, 2... Reference voltage setting section, 3... Integrating circuit, 4... Level detection circuit, 5... Relay drive circuit, 61. Output relay, 7... Constant voltage circuit, 8...
・Differential circuit. Figure 2

Claims (1)

[Claims] 0) In a static protection regulator that requires a control power source and whose voltage is regulated by a constant voltage circuit and supplied to a reference voltage setting section, level detection circuit, etc., the output voltage of the constant voltage circuit is differentiated. 1. A static protective relay, characterized in that a circuit is provided to increase the detection level of a level detection circuit, and its output is taken into consideration in the direction of increasing the detection level of a level detection circuit.