JPH0326773Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is applicable to live connection work such as on switchboards.
The present invention relates to a different phase connection prevention device for an AC circuit, which is provided to prevent short circuit accidents caused by incorrect connections.

(Conventional technology) Recently, in distribution line construction, power is supplied to the load from a generator mounted on a mobile power supply vehicle instead of a power source during construction, and power outages are limited to only one section including the construction work, and other loads are There is a strong demand for uninterrupted operation. However, when switching between the power source and the generator, if the generator output is simply set and turned on based on a guess without measuring the load immediately before switching, as in the past, the generator may overload. Due to the load, there is a risk of an emergency power outage. Furthermore, even if there is no power outage, abnormal transient voltages often occur during switching. In order to eliminate such troubles, it is sufficient to measure the amount of load immediately before switching, adjust the generator output to match this amount, and then turn the generator on to the load. This load measurement circuit needs to be connected in parallel between the load side and the power source of a live wire open part such as a pole switch that is opened during construction. When connecting a parallel circuit to an open part of a live wire in this way, if the connection is incorrect, a short circuit will occur. However, with conventional technology, the only option is to measure and confirm the voltage between terminals that appear to be facing each other with a measuring device, and then carefully decide on the connection method.

(Problems to be Solved by the Invention) In the conventional method described above, there may be errors in the connection method even if sufficient careful consideration has been made based on the measured results. At that time, time, expenses,
Not only is labor wasted, but in some cases, there is a risk of serious accidents occurring.

It is conceivable that most of the steps from the measurement to the connection of the parallel circuits be performed using pulse signals and electronic logic circuit processing thereof, but this has the drawback that the circuit becomes complicated.

The purpose of this invention is to solve these problems, and when you connect some device to a live line, if you try to close the disconnector installed in the device, but the connection is incorrect, it will cause the disconnection to occur. To provide a highly reliable device for preventing out-of-phase connection in an AC circuit, which is configured with a simple circuit to prevent circuits from closing.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the device for preventing out-of-phase connections in AC circuits according to the present invention prevents short-circuit accidents caused by incorrect connection when parallel circuits are connected to live open portions of distribution lines. In the out-of-phase connection prevention device provided to prevent this, a first voltage transformer PT ₁ connected to the power supply side U, V, W of the live open part 2 of the distribution line 1
and a second voltage transformer PT 2 connected to the load sides R, S, T of the live open section ₂ , and the secondary sides of the first voltage transformer PT ₁ and the second voltage transformer PT ₂ . u, v,
The first contact PB1a of the test push button switch, the first contact 7b of the auxiliary relay 7a, and the first Voltage relay 5a, series circuit, and second contact PB1 of the test push button switch
b, the second contact 7c of the auxiliary relay 7a, and the second voltage relay 6a. Contact 5b and the second
It has a connection control circuit configured by inserting a parallel circuit of contacts 6b of the voltage relay 6a between the auxiliary relay 7a and its drive power source, and connects the third contact 7d of the auxiliary relay 7a to the live wire open portion 2. The configuration is such that it is inserted in series with the drive circuit 3a of the connection means 3b.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a connection diagram showing one embodiment of the present invention.

Fig. 2 is for explaining the operating principle of the present invention.
FIG. 3 is an explanatory diagram showing voltages applied to first and second voltage relays.

As shown in FIG. 1, in this embodiment, the live wire open part of the wiring 1 to be connected is, for example, the top switch 2, and the power supply side U, V, W of this pole switch 2 is
is connected to the primary side of the first voltage transformer _PT1 . Further, the load sides R, S, and T of the pole switch 2 are connected to the primary side of a second voltage transformer PT ₂ . Of the outputs U, V, and W on the secondary side of the first voltage transformer PT ₁ , the V output is grounded. Also, the outputs r, s, on the secondary side of the second voltage transformer PT ₂ ,
The s output of t is grounded. However, the outputs of r, s, and t are expressed assuming that the primary side of the second voltage transformer PT ₂ is connected correctly; if the connection of the primary side is different, the r, s, and t outputs of the secondary side are
The order of s and t also differs accordingly. Between the secondary output u of the first voltage transformer PT ₁ and the secondary output r of the second voltage transformer PT _2, the first contact PB1a of the test push button switch and the first voltage relay are connected. 5a and a series circuit of the first contact 7b of the auxiliary relay 7a are connected. Also the first voltage transformer PT ₁
The second contact point of the test push button switch is connected between the secondary output w of the PT2 and the secondary output t of the second voltage transformer _PT2 .
PB1b, second voltage relay 6a and auxiliary relay 7
A series circuit of a second contact 7c is connected. In these two sets of series circuits, if the main means for connecting the open part 2 of the live line or the connection of the disconnectors 3a and 3b to the live line is not normal, the first and second voltage relays will operate. This is a circuit that detects that the phase is out of phase.

Contacts 5b and 6b of the first and second voltage relays 5a and 6a are connected in parallel and inserted between the auxiliary relay 7a and its drive power terminal 8a. Therefore, the auxiliary relay is activated when either one of the contacts 5b, 6b closes.
Note that the parallel circuit of the contacts 5b and 6b is further connected in parallel with the series circuit of the contact 7e of the auxiliary relay 7a itself and the contact of the push button switch _PB2 .
Once the auxiliary relay 7a is activated, it will not be restored unless the push button switch _PB2 for self-hold release is pressed. The third contact point 7d of this auxiliary relay 7a is connected to the drive section 3a of the connection means (main shield disconnector) 3b of the live line open portion (pole switch) 2 and the drive switch 4 of the main shield disconnector 3b. Since the auxiliary relay 7a is inserted in series with the series circuit of
If the main switch 3b is activated, the main switch 3b is configured not to close even if the main switch 3b is pressed. Note that the first voltage transformer PT ₁ and the second voltage transformer may be omitted by utilizing the output of a voltage transformer provided for a purpose other than the present invention. Further, 8b is a negative input terminal of the power source for driving the auxiliary relay 7a.

Next, the operating principle and operation of this embodiment will be explained.

Figure 2 shows U, V, and
For connection to W, each possible connection method to the load side R, S, T and the voltage applied to the voltage relay at that time are shown as the voltage in the case of the first voltage relay, and the voltage in the case of the second voltage relay. The case of a voltage relay is shown as the voltage of . Figures a to c are for the case where the phase rotation direction is connected in the forward direction, and figure a is for the case where the phase rotation direction is connected in the same phase.
Figures b and c in the figure are different-phase connections. Moreover, d to f in the same figure are cases where the phase rotation directions are connected in opposite directions. As shown in Figure 2, only when the phase rotation direction is the same and the same phases are connected to each other, the voltage across the first and second voltage relays is zero; otherwise, all Due to the phase shifter, line voltage E is applied in the phase rotation direction even in positive phase connection, and 2E is applied in reverse phase connection.

The present invention takes advantage of this characteristic and, as shown in Figure 1, is a voltage transformer with a single-line ground fault.
Voltage relays 5a and 6a are connected in series with PT ₁ and PT ₂ .

When using this embodiment, as shown in Fig. 1, after the live connection to the distribution line 1 is completed, press the push button switch whose contacts are PB1a and PB1b, and if the connection is normal, Both the first voltage relay 5a and the second voltage relay 6a do not operate.

Therefore, since the auxiliary relay 7a also does not operate, the contacts 7d of the auxiliary relay 7a remain closed, so by pressing the push button switch 4 for driving the main shield disconnector, the main shield disconnector 3b is activated. It is possible to invest.

If the connection is incorrect, voltage is applied to the first voltage relay 5a and the second voltage relay 6a, the contacts 5b and 6b close, and the auxiliary relay 7a operates, and the auxiliary relay 7a Self-contact point 7e
At the same time, the contacts 7b and 7c are opened, disconnecting the first and second relays 5a and 6a, and the contact 7d is also opened, so even if the push button switch 4 is pressed, the main switch 3b will not close. becomes impossible. In this way, it is possible to prevent the main cutter 3b from being erroneously turned on.

(Effects of the invention) As explained above, the invention has two voltage transformers connected to the power supply side connected to the live line and the load side.
A voltage relay is connected between the terminals corresponding to each of the next outputs, and when the voltage relay is activated, the auxiliary relay operates and opens the main switch or disconnection drive circuit, so if a wrong connection is made, the main This has the effect that even if you try to insert a disconnector, it will not work.
Short-circuit accidents caused by incorrect connections on the power supply side and load side can be prevented by using a highly reliable device with a simple circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an embodiment of the different phase connection prevention device for an AC circuit according to the present invention. FIG. 2 is an explanatory diagram showing the voltage applied to the voltage relay of the embodiment shown in FIG. 1. 1... Distribution line, 2... Pole switch, 3a... Main shield breaker, 3b... Main shield breaker contact, 4... Main shield breaker drive push button switch, 5a... First voltage relay, 5b... Contact of first voltage relay, 6
a...Second voltage relay, 6b...Contact of the second voltage relay, 7a...Auxiliary relay, 8a, 8b...
...auxiliary relay drive power input terminal, PT ₁ ... first voltage transformer, PT ₂ ... second voltage transformer.

Claims (1)

[Scope of Claim for Utility Model Registration] In a different phase connection prevention device provided to prevent a short circuit accident due to incorrect connection when a parallel circuit is connected to an open part of a live line of a distribution line, the power supply of the open part of the live line is provided a first voltage transformer connected to the load side of the live wire open section; a second voltage transformer connected to the load side of the live open section; and two of the first voltage transformer and the second voltage transformer.
A series circuit of the first contact of the test push button switch, the first contact of the auxiliary relay, and the first voltage relay, which are connected between the other corresponding terminals, with one line on the next side grounded, and the test 2nd push button switch
a phase detection circuit consisting of a series circuit of a contact of the auxiliary relay, a second contact of the auxiliary relay, and a second voltage relay;
A connection control circuit configured by inserting a parallel circuit of contacts of the first voltage relay and contacts of the second voltage relay between the auxiliary relay and its driving power source,
A phase connection prevention device for an AC circuit, characterized in that the third contact of the auxiliary relay is inserted in series with the drive circuit of the connection means of the live wire open portion.