JPS6228022Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electrical interlock device for three electrically operated circuits and disconnectors.
Conventionally, a power distribution system as shown in FIG. 1 has been commonly used to increase transformer capacity and load capacity or to minimize power outages.

Figure 1 is a general power distribution system diagram. In Fig. 1, a busbar connection circuit connecting the system of transformer Tr1 and the system of transformer Tr2 is connected to the circuit breaker NFB _3.
(hereinafter referred to as the bust tie breaker) is always OFF.
(off), and the system of transformer Tr1 and transformer Tr2
The power is supplied to each of the loads L ₁ and L ₂ independently from the other systems. Now, if the main line circuit or disconnector NFB1 trips due to a short-circuit accident in the system of the transformer Tr1, the power supply to the load _L1 will be stopped, causing an inconvenience. Therefore, the bust tie breaker
By turning on NFB3, power is supplied to load _L1 from the transformer Tr2 system, minimizing power outage of load _L1 . The same applies when the main line circuit or disconnector NFB2 trips. However, if the normally operating main line circuit breakers NFB1 and NFB2 are ON, if you accidentally turn on the bus tie breaker NFB3, the transformer Tr1 system and the transformer Tr2 system will become parallel, and the transformer Tr1 system and transformer Tr2 system will become parallel. The impedance of the transformer and the power supply impedance above the primary side of the transformer are each halved. Therefore, if a short circuit occurs on the load side of the branch circuit or disconnector NFB4, a considerably larger short circuit current will flow than a short circuit during normal operation, causing the branch circuit or disconnector NFB4 to disconnect. There were times when we ran out of capacity. As a countermeasure to this problem, it was necessary to use an expensive branch circuit breaker NFB4 with a large breaker capacity.

This idea was made in order to eliminate the drawbacks of the conventional ones as mentioned above, and when two of the three circuit disconnectors are ON, the remaining one
The circuits and disconnectors on the stand are turned on (ON) by electrical operation.
The object of the present invention is to provide an electrical interlock device for three circuit breakers and disconnectors by so-called electrical operation. An embodiment of this invention will be described below with reference to the drawings.

FIG. 2 is a circuit configuration diagram showing one embodiment of the electrical interlock device according to this invention, in which the auxiliary switch AX1 is built in the main circuit and the disconnector NFB1. The auxiliary switch AX2 is built into the main line circuit and disconnector NFB2. Auxiliary switch AX3 is a bus tie breaker
Built into NFB3, these auxiliary switches AX1, AX2, and AX3 are linked to the contacts of each circuit and disconnector, and the circuit and disconnector are connected to each other.
The auxiliary switch operates OFF when it is ON, and the auxiliary switch operates OFF when the circuit or disconnector is OFF or tripped.
It works ON. The auxiliary switch AX3 and the first electrical interlock release switch SW1 are connected in parallel to form a first parallel circuit A. The ON operation switch 1 of the first electric operation device _M1 is connected in series to this first parallel circuit A, thereby forming an ON operation circuit of the first electric operation device _M1 . Further, the ON operation switch 3 of the second electric operation device _M2 is connected in series to the first parallel circuit A, thereby forming an ON operation circuit for the second electric operation device _M2 . Auxiliary switch AX1 and AX2
and a second electrical interlock release switch.
SW ₂ are connected in parallel to form a second parallel circuit B. The ON operation switch 5 of the third electric operation device _M3 is connected in series to this second parallel circuit B, thereby forming an ON operation circuit of the third electric operation device _M3 . The OFF (opening) operation switches 2, 4, and 6 of the first, second, and third electric operation devices M ₁ , M ₂ , and M ₃ are the respective electric operation devices.
Connected between M ₁ , M ₂ , M ₃ and AC power supply G, the first, second and third electric operating devices M ₁ , M ₂ , M ₃
It constitutes the OFF operation circuit. The auxiliary switches AX1, AX2, and AX3 are break contacts of the first, second, and third electric operating devices _M1 , _M2 , and _M3, respectively. Next, this operation will be explained.

In FIGS. 1 and 2, the main line circuit breakers NFB1 and NFB2 are always ON, and the bus tie breaker NFB3 is OFF. Because the main line circuit disconnectors NFB1 and NFB2 are ON, the auxiliary switch
AX1 and AX2 are OFF. Therefore, when the second electric interlock release switch SW2 is OFF, even if the ON operation switch 5 is turned ON by mistake, the ON operation circuit of the third electric operation device _M3 is opened. Bus tie breaker NFB3 is turned ON
Can not. Main line circuit breakers NFB1 and NFB2
Either one is ON and the other is tripped (or
OFF), one of the auxiliary switches AX1 and AX2 is ON, so the ON operation switch 5
When you turn on, the third electric operating device _M3 turns on.
The operating circuit is closed and the bus tie breaker
NFB3 can be turned ON. Therefore, continuity of power supply is ensured by minimizing power outage of load _L1 or _L2 . Also, if bus tie breaker NFB3 is ON, the main line circuit or disconnector NFB1 or NFB2 is turned on.
ON and main line circuit disconnector NFB2 or
When NFB1 is OFF, auxiliary switch AX3 is OFF
Therefore, if the first electrical interlock release switch SW ₁ is OFF, even if ON operation switch 3 or 1 is turned ON by mistake, the main line circuit or disconnector NFB2 or NFB1 will not be closed (ON). )Can not. The electrical interlock described above can be written in an easy-to-understand manner as follows.

(1) NFB1-ON, NFB2-ON, NFB3-cannot be turned on (2) NFB1-ON, NFB2-OFF, NFB3-can be turned on (3) NFB1-OFF, NFB2-ON, NFB3-can be turned on (4) NFB1- ON, NFB3-ON, NFB2-cannot be turned on (5) NFB2-ON, NFB3-ON, NFB1-cannot be turned on Electrical interlock release switch SW1,
SW2 is normally OFF, but if you want to cancel the electrical interlock in an emergency, use the first and second electrical interlock release switches SW1 and SW2.
When turned ON, the electrical interlock described above is canceled. It is desirable that the first and second electrical interlock release switches SW1 and SW2 be provided with locks to prevent erroneous operation.

In addition, although the case of a circuit switch or a disconnector was explained in the said Example, it may be other switching devices, such as a disconnector or an electromagnetic switch, etc., and it will produce the same effect as the said Example. We also explained the case where this idea was applied to the power distribution system as shown in Figure 1.
It can be used anywhere where electrical interlock is required, such as a circuit board or disconnector, with the same effect.

As described above, according to this invention, by combining an auxiliary switch, an electric operating device, and an electric interlock release switch, when two of the three circuit breakers are ON, the remaining one It is not possible to turn on (ON) the circuit or disconnector of the stand by electrical operation.
It is possible to electrically interlock three circuits and disconnectors by so-called electrical operation.

[Brief explanation of the drawing]

Figure 1 is a general power distribution system diagram. FIG. 2 is a circuit diagram showing an embodiment of the electrical interlock device according to the invention. In the figure, NFB1 and NFB2 are main line circuit breakers, NFB3 is a bus tie breaker, AX1,
AX2 and AX3 are auxiliary switches, M ₁ , M ₂ and M ₃ are electric operating devices, SW1 and SW2 are first and second electrical interlock release switches, 1, 3 and 5 are
ON operation switches 2, 4, and 6 are OFF operation switches, and A and B are first and second parallel circuits.

Claims (1)

[Scope of utility model registration request] First, second, and third electric operating devices for opening and closing the first, second, and third switching devices, and a break contact of the third electric operating device and a first interlock release switch are connected in parallel. a first parallel circuit in which the break contacts of the first and second electric operating devices and a second interlock release switch are connected in parallel, respectively;
closing operation switches for the first and second electrical operating devices connected between the electrical operating device and the first parallel circuit, and between the third electrical operating device and the second parallel circuit; An electrical interlock device comprising an operating switch for turning on the third electrical operating device connected thereto.