JPH0463411A - Device and method of conducting on-load tap changing to tap changer for multistage switch - Google Patents

Abstract

PURPOSE: To reduce the switching time of a tap selection machine by mechani cally forcing and controlling an output conversion contact and two continuation current contacts, so that only the continuation contact of a load branch where a current flows at a still position is closed. CONSTITUTION: A device has taps 1, 2, and 3 and two load branches with two switching contacts being installed in series, where a contact 4.1 is provided in series with a contact 7 at one load branch, and a contact 4.2 is provided in series with a contact 6 at the other. In a parallel circuit, continuing current contacts 8 and 9 are connected in parallel, and a transistor resistor 5 is provided between the contacts of any load branch. Two contacts 4.1 and 4.2 that counterpose the tap selector of each load branch are composed as a common double-pole tap switcher 4. And the other two contacts 6 and 7 and two continuing current contacts 8 and 9 that counterpose a load output edge 10 of each load branch are constituted as contacts that are mechanically forced and controlled, so that only the continuing contact of the load branch where a current flows is closed at a still position, thus performing the switching operation quickly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is characterized in that two load branches are each connected to one tap of a multistage transformer by a tap selector, and each load branch has two series connections. On-load tap switching with switching contacts, to which a continuous current contact for continuous current introduction is connected in parallel, connected to the connection point of both switching contacts of each load branch. A multi-stage transformer in which a transition resistor, which can be switched on briefly during the process, is arranged between the two load branches and switches from the initially energized load branch to the current-carrying load branch. The present invention relates to an apparatus and associated method for performing on-load tap switching for a tap selector of a multi-stage switch.

[Prior Art] Such an on-load tap changer is disclosed in West German Patent No. 252.
It is known from specification No. 0670.

In this device, two switching contacts act as main switching contacts or resistive switching contacts, depending on the switching direction, and the corresponding transformer to be switched is subjected to a full load current which leads to strong wear on the main switching contacts. Or, in the case of no-load operation, there is the advantage that contact wear progresses in the same way in both contacts, regardless of whether a very small load current is applied, which causes less wear on the contacts. The difficulty with the known circuit is that, depending on the direction of rotation of the drive, the single-pole tap selector, which gives the attachment of the function of the switching contact as a main switching contact or as a resistive switching contact, does not allow the entire load to pass through to the load induction. The point is to switch the current.

This switching process therefore takes place as quickly as possible, which is why, even in the case of known switching devices, it is necessary to move the switching device temporally in front of the switching contact by means of a stored energy drive. However, this means, on the one hand, that some of the energy present in the stored energy device already has to be used to operate the tap selector and is therefore no longer available for reliably operating the actual switching contact. , on the other hand, the energy storage must be designed so that the total switching time from one stage to the other becomes longer by the switching time of the tap selector, which becomes the switching time of the continuously operated main contact or resistive contact. means.

In summary, multiple switching procedures need to proceed in the earliest possible order. This progression, or contact operation, places high demands on the energy storage device, complicates its construction, and increases the failure rate and frequency of malfunctions of the overall tamp changer.

[Problem of the Invention] The object of the present invention is to perform only the minimum value of the switching operation using an energy accumulator in the shortest possible time and in the earliest possible order, to perform the remaining switching operations without current, and to store energy before and after disassembly. The object of the present invention is to modify the known method and device for performing on-load tap switching so that it can be performed independently of the equipment.

[Means for Solving the Problem] The above problem can be solved by the present invention, in the case of the method for performing tap switching under load of the type mentioned at the beginning, by replacing the two switching contacts on the tap selector side with a two-pole switching device. The switching contact belonging to the load branch through which current flows in the stationary state is always closed, and the other two switching contacts on the output side are formed as output switching contacts, and these switching contacts are configured as output switching contacts. The switching contact and the two current-current contacts are arranged such that in the rest position only the current-carrying current-carrying contact of the load branch is closed.
This problem is solved by constructing the contact as a mechanically forcibly controlled contact.

Furthermore, the above-mentioned problem can be solved by the present invention, in the case of a device that performs on-load tap switching of the type mentioned at the beginning, in the process of switching from a energized load branch to a load branch through which current flows, the following switching order is required. ,I. Close the load switching contacts of the current-carrying load branches; II. Opening the current carrying current contact of the load branch; III. Close the load switching contacts of the load branches that will carry lightning current; IV. Close the load switching contacts of the load branch through which lightning current flows, V. Close the continuous current switching contact of the load branch that will carry lightning current; 1. Open the load switching contact of the load branch that will carry lightning current; VII. Solved by replacing the two-pole switch.

〔Example〕

This invention will be explained in more detail below based on Examples.

The multistage transformer to be switched has taps 1, 2.3.

Between the two taps 2.3, in the case of the device shown in FIG. Child 7
On the other hand, a contact 4.2 is arranged in series with the contact 6.

In this parallel circuit, each continuous current contact 8.9 is connected in parallel.

A transition resistor 5 is arranged between the contacts of every load branch.

The two contacts 4.1, 4.2 respectively facing the tap selector of each load branch are configured as a common two-pole tap changer 4. In the other two contacts 6.7 facing the load output 10 of each load branch, continuous current contacts 8,
The contact of the load switch which is mechanically connected to 9 is important. FIG. 2 illustrates an on-load tap changing method using the apparatus shown in FIG. i.e. a) continuous current contact 9 is closed and current is flowing to tap 3;
From there, it flows to the output end 10 via this contactor 9.

b) The load switching contact 7 of the load branch through which the current passes is closed, and the current flows via the continuous current contact 9 and the load switching contact 7.

C) Continuous current contact 9 opens. The current flows exclusively via the load switching contacts 7.

d) Close the load switch contact 6 of the load branch connected to the tap 2 to be switched.

e) Open the load switch contact 7. The current is contact 4゜1,
It flows via the transition resistor 5 and the continuous current contact 8.

f) Continuous current contact 8 closes. Current flows from the tap 2 via the continuous current contact 8 to the output 10, and at the same time a balancing current flows from the tap 3 via the contact 4.1, the transition resistor 5 and the contact 6.

g) Load switch contact 6 opens. Current is exclusively tap 2
from the load output terminal 1 via the transition resistor 5 and the contact 8
Flows to 0.

h) The two-pole tap selector 4 switches. That is, switch 4
．． 1 opens and switch 4.2 closes. This on-load tap switching is completed.

Steps i) to p) return to the output position through another analogously proceeding switching process.

FIG. 3 shows another exemplary on-load tap changer.

In this case, two individually operable continuous current contacts 8,
9 has been replaced by a single switching contact. This switching contact connects the contact 8.9 opposite the tap 2.3 in each load branch to the load output 10 and acts directly as a bypass. In this embodiment, the continuous current contact configured as a selection contact is mechanically coupled to the other contacts so that the same process sequence occurs.

FIG. 4 shows switching to another tap again (step a-
h), the corresponding switching process for switching back again (steps 1-p) is shown.

In the case of two switching processes, it can be seen from the switching sequence that only the load switching contact 6.7 needs to be actuated by the spring energy accumulator as soon as possible in order to quickly extinguish the arc. Whether in the case of a two-pole switch 4 or in the case of continuous current contacts 8, 9 or one continuous current contact, the switching speed is, on the contrary, not subtle, i.e. they switch in each case without output. .

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of an on-load tap changer. Figures 2a-h and 2i-p show the associated switching process. FIG. 3 shows a second embodiment of the on-load tap changer. 4a-h and 4i-p further illustrate the associated switching process. Reference symbols in the figure: 1.2.3...Tap, 4...Switcher, 4.1, 4.2...Tap side contact, 6.7...Output end side contact ( Load switching contact) 8.9... Continuous current contact, 10... Output terminal. Agent: Mitsuyoshi Esaki (3 others)

Claims (2)

[Claims] 1. The two load branches are each connected to one tap of the multistage transformer by a tap selector, and each load branch has two switching contacts in series, to which continuous current is introduced. Continuous current contacts for both loads are connected in parallel, and one transition resistor in each case, which can be switched on briefly during the process of on-load tap switching, is connected to the connection point of both switching contacts of each load branch. In a device that performs on-load tap switching for a tap selector of a multistage switch of a multistage transformer, which is installed between branches and switches from a load branch that is initially energized to a load branch that is energized. , the two switching contacts on the side of the tap selector are formed as a two-pole switch, the switching contacts belonging to the load branch through which the current flows in a stationary state are always closed, and the switching contacts on the output side forming two switching contacts as output switching contacts,
These output switching contacts and the two current-current contacts are configured as mechanically forced contacts such that in the rest position only the current-carrying current-carrying contact of the load branch is closed. A device characterized by: 2. In a method of performing on-load tap switching using the device according to claim 1, the following switching order is performed in the process of performing on-load tap switching from an energized load branch to a load branch through which current will flow. , I. Close the load switching contacts of the load branches carrying current; II. Open the continuous current contacts of the current-carrying load branches; III. Close the load switching contacts of the load branch that will carry current; IV. Close the load switching contacts of the load branches carrying current, V. Close the continuous current switching contacts of the load branches that will carry current; VI. Open the load switching contacts of the load branches that will carry current; VII. Replace the two-pole on-load tap changer. A method characterized by: