CN100466128C - Load Grading Switches with Motor Drivers - Google Patents

Abstract

The invention relates to a load tap changer with a motor drive, wherein the necessary monitoring and restart functions are carried out by means of inductive proximity sensors which are arranged on the load transfer switch for position detection thereof, said sensors interacting with separate cam switches which are actuated by cams according to a specific sequence. According to the invention, the result involves actuation of a plausibility check for each change and a motor protection circuit breaker is actuated if deviation occurs from a normal state.

Description

Load Grading Switches with Motor Drivers

technical field

The invention relates to a load grading switch with a motor driver.

Background technique

Such a load grading switch for internal installations is known from the applicant's company publication "Laststufenschalter AVT-Betriebsanleitung (Operating Instructions for Load Grading Switch AVT)", printed edition BA 163/01de, 0802/500, which serves to regulate loads The transformation ratio of a dry-type transformer. Such known load grading switches work according to the principle of fast resistive switching. It has a selector for pre-selecting the new winding tap to switch to with no load, and a load switch for subsequent actual switching. Use vacuum switching cells (Vakuumschaltzellen) as load changeover contacts. In this case the motor drive for initiating switching is integrated into the housing of the load rating switch.

The applicable standards here, such as IEC 60214 and VDE 0532, stipulate that: Motor drives have direction of rotation monitoring and include means to ensure that switching to one direction that has started is automatically terminated. The above-mentioned process must obtain the information about the rotation direction as a prerequisite. In order to ensure that this requirement is met, a rotating field test relay for monitoring the direction of rotation and a bistable relay (locking relay) for automatically terminating the switching initiated are provided in known load stepping switches. But there are two disadvantages in the above-mentioned electronic components: the one is expensive, and the other is that it is prone to problems under severe environmental conditions.

Contents of the invention

It is therefore the object of the present invention to provide a load grading switch of the above-mentioned type with a motor drive, in which the above-mentioned safety requirements can be achieved in a simple and economical manner.

This task is achieved by means of a load staging switch with a motor drive for uninterrupted switching between winding taps of a tapped transformer under load, in which there is a A selector for pre-selecting new winding taps on the load ground and a load converter for actual switching under load, wherein the selector and load converter are jointly manipulated by a coupling lever of the motor drive so that the motor drive on the one hand On the other hand, the selector drive that actuates the selector pulls up the force accumulator for the subsequent actuation of the load converter, wherein the motor drive has an electric motor that can be activated in each case by means of a motor protector depending on the direction of rotation, and at A motor protection relay is provided in the electric circuit of the motor, wherein an inductive distance sensor is provided on the load converter, which detects the individual positions of the load converter; a cam track operating in relation to the direction of rotation is provided on the coupling rod and two cam switches corresponding to the cam track; another cam track that works independently of the direction of rotation is set directly on the selection drive, which corresponds to the third additional cam switch; and a distance sensor is provided , the electrical device for comparing the actual switch positions obtained by the two cam switches and the other third cam switch with the normal state of the load classification switch each time it is operated, so that when at least one of the above actual switch positions When a switch position deviates from the normal operating state, the motor protection switch can be activated.

The load classification switch in the present invention has different new features, and the combination of these new features meets the above-mentioned safety requirements. Among them, the direction of rotation monitoring and the restart of the motor drive are deduced from the basically existing report information. It is particularly advantageous that no additional mechanical components are required; the above-mentioned rotating field test relay and bistable relay can be omitted without replacement.

To achieve the above goals, the following features are proposed:

First, an inductive distance sensor is set on the load converter of the load classification switch to detect its position.

Furthermore, devices for trip monitoring (Entlinkungsüberwachung) are provided on the coupling rod between the motor drive and the load classification switch, which have cam switches.

In addition, means are provided for reporting information on the mechanical operation of the motor drive; it obtains said reporting information directly on the selector drive by means of a direction-independent cam track.

Finally, electrical means for making operational reporting information to (known) motor protectors are provided.

Description of drawings

The invention is described in more detail below by way of example. as the picture shows:

Figure 1 shows the structure of an inductive distance sensor,

Figure 2 shows the device for trip monitoring on the coupling bar between the motor driver and the load classification switch,

Fig. 3 shows the means for making machine operation report information on the selection drive,

Figure 4 shows a complete circuit diagram of a motor driver as an integral part of a load grading switch according to the present invention,

Figure 5 shows a detailed diagram of the circuit with the safety device,

Fig. 6 shows a schematic diagram of the switching process from one winding tap of a dry-type transformer to another (adjacent) winding tap.

Detailed ways

Fig. 1 shows how to acquire the position of the load converter by means of inductive distance sensors S70, S71 on the load converter. Wherein a direct/indirect reporting message is generated, which is multiplied by auxiliary protectors K13 and K14 which will be described further below. The load converter switches itself about 20 degrees before a switching is complete. Instead, in the entire embodiment, an overall rotation angle of 360 degrees is initiated for each load transition.

Figure 2 shows in detail the arrangement for trip monitoring. For this reason, a cam rail is set on the connecting rod between the motor driver and the grading switch. As shown in the blackened part in the figure, the cam rail expands 130 degrees in one direction, so that the corresponding cam switches S23 and S24— - According to the respective actual setting and controlled running direction - open 25 degrees after the start of the switch, or close 25 degrees before the end of the switch.

Figure 3 shows an arrangement for machine operation reporting of a motor drive. The figure shows a direction-independent operating cam track which is arranged directly on the selection drive. In this case, the cam switch S13 is opened for 35 degrees after the switching starts, or is closed for another 35 degrees before the switching ends. The movement of the selector starts automatically only when the rotation angle is greater than 35 degrees.

FIG. 4 shows a circuit diagram according to the invention, which also includes other known but necessary components to illustrate the overall function. The same applies to the actual monitoring unit shown in FIG. 5 . As shown in Figure 4 and Figure 5:

F2 Arc monitoring unit

H1 signal light

K1 Motor Protector

K2 Motor Protector

K13 Auxiliary protector for distance sensor S70

K14 Auxiliary protector for distance sensor S71

K20 step switch relay

K29 Timing relay

M1 motor

Q1 Motor protection switch

S3 High/Low Switch

S4 Limit switch for K1

S5 for limit switch of K2

S8 A and B: safety switch

S13 Cam switch

S23 Cam switch

S24 Cam switch

S38 Potentiometer contact

S70 distance sensor

S71 distance sensor

X... Terminal

The operation mode of the load grading switch with motor driver according to the present invention will be stated again below, and the safety device of the load grading switch which meets the technical requirements stated at the beginning of the description will be emphasized. After controlling one of the motor protectors K1 and K2 to work, the motor M1 in the motor driver starts to start. After opening 25 degrees, the cam switches S23/S24 exchange positions with each other (see Figure 2). 35 degrees after the start of switching, another cam switch S13 will switch the restart device/rotation direction monitoring device to activate (see Figure 3). When the cam switch S13 is activated, the load converter and the inductive distance sensors S70/S71 and their auxiliary protectors K13/K14 (see Figure 1) for multiplying the reporting signal do not exchange positions while monitoring the tripped cam switch S23, S24 (see FIG. 2 ) do not exchange positions either.

During this period of time, the following work statuses were queried:

Even position of load converter (K13 activated, K14 not activated)

Running direction to the right (K2 starts, K1 does not start, S24 starts, S23 does not start)

Even position of load converter (K13 activated, K14 not activated)

The running direction is left (K1 is started, K2 is not started, S23 is started, S24 is not started)

Uneven position of load converter (K14 activated, K13 not activated)

Running direction to the right (K2 starts, K1 does not start, S23 starts, S24 does not start)

Uneven position of load converter (K14 activated, K13 not activated)

Running direction to the left (K1 starts, K2 does not start, S24 starts, S23 does not start)

According to the above sorting rules, all possible working states can be queried. The query itself is obtained through the electrical miswiring of the reporting information contacts mentioned above. These contacts act directly on the motor protection switch Q1 (rotation direction monitoring) or the motor protectors K1, K2 (restart device).

The switching process will be described in detail again below according to the circuit diagram shown in FIG. 4 . The control process itself works according to the principle of step switching, and complies with the requirements of IEC60214. The two motor protectors K1 and K2 control the motors to run in different rotation directions respectively. The motor protection switch Q1 protects the motor from overloading and provides a tripping coil for cutting off the circuit. All angle descriptions employed below refer to a full rotation angle of 360 degrees per switch.

a) Uneven position of the load converter, control to the right

The load converter is in an uneven position, S71 runs, K14 pulls up, and S23 runs. After controlling the motor protector K2, the motor M1 runs in the "right" running direction. After opening 25 degrees, the cam switch for trip monitoring reaches the designated position, and the cam switch will maintain this position throughout the inspection period (35 degrees to 325 degrees). According to Fig. 2, the state remains unchanged in this case; S23 remains active and S24 does not. Cam switch S13 (Fig. 3) comes into operation after opening 35 degrees and initiates the verification and restart phase.

Voltage is applied to cam switch S13 (activated) and to the open contact of auxiliary protector K13 (not activated) for multiplying the position reporting information of the load converter, with voltage applied to cam switch S24 (not activated). If not activated due to the correct direction of rotation S24, voltage will be applied to the coil of the motor protector K2 for the "right" direction of rotation; ensure a restart until the release of the cam switch S13. If S24 is activated eg due to a wrong rotating field connected to the terminal, the motor protection switch Q1 will be released by opening the cam switch S13 and via the auxiliary contacts of the motor protector K2: 53-54.

b) The position of the load converter is uneven, control to the left

The load converter is in an uneven position, S71 runs, K14 pulls up, and S23 runs. After controlling the motor protector K1, the motor M1 runs in the "left" running direction. After opening 25 degrees, the cam switch for trip monitoring reaches the designated position, and the cam switch will maintain this position throughout the inspection period (35 degrees to 325 degrees). As shown in Figure 2, S24 runs; S23 falls back. Cam switch S13 (Fig. 3) comes into operation after opening 35 degrees and initiates the verification and restart phase.

Cam switch S24 (activated) has voltage applied to cam switch S13 (activated) and to the open contact of auxiliary protector K13 (not activated) for multiplying the position reporting information of the load converter. If activated due to the correct direction of rotation S24, voltage will be applied to the coil of the motor protector K1 for the "left" direction of rotation; ensure a restart until the release of the cam switch S13. If S24 is not activated eg due to a wrong rotating field connected to the terminal, the motor protection switch Q1 will be released by opening the cam switch S13 and via the auxiliary contacts of the motor protector K1:53-54.

c) The load converter bit is even, control to the right

The load converter is in a uniform position, S70 runs, K13 pulls up, and S24 runs. After starting the motor protector K2, the motor M1 runs in the "right" running direction. After opening 25 degrees, the cam switch for trip monitoring reaches the designated position, and the cam switch will maintain this position throughout the inspection period (35 degrees to 325 degrees). According to Fig. 2, the state remains unchanged in this case; S24 remains active and S23 does not. Cam switch S13 (Fig. 3) comes into operation after opening 35 degrees and initiates the verification and restart phase.

Voltage is applied to cam switch S13 (activated) and to the open contact (not activated) of auxiliary protector K14 for multiplying the position reporting information of the load converter. If not activated due to the correct direction of rotation S23, voltage will be applied to the coil of the motor protector K2 for the "left" direction of rotation; ensure a restart until the release of the cam switch S13. If S23 is activated eg due to a wrong rotating field connected to the terminal, the motor protection switch Q1 will be released by opening the cam switch S13 and via the auxiliary contacts of the motor protector K2: 53-54.

d) The position of the load converter is even and controlled to the left

The load converter is in a uniform position, S70 runs, K13 pulls up, and S24 runs. After starting the motor protector K1, the motor M1 runs in the "right" running direction. After opening 25 degrees, the cam switch for trip monitoring reaches the designated position, and the cam switch will maintain this position throughout the inspection period (35 degrees to 325 degrees). As shown in Figure 2, S23 runs; S24 falls back. Cam switch S13 (Fig. 3) comes into operation after opening 35 degrees and initiates the verification and restart phase.

Voltage is applied to cam switch S23 (activated) for cam switch S13 (activated) and the auxiliary protector K14 opener (not activated) for multiplying the position reporting information of the load converter. If S23 is activated due to the correct direction of rotation, voltage will be applied to the coil of the motor protector K1 for the "left" direction of rotation; ensure a restart until the release of the cam switch S13. If S23 is not activated eg due to a wrong rotating field connected to the terminal, the motor protection switch Q1 will be released by opening the cam switch S13 and via the auxiliary contacts of the motor protector K1:53-54.

Since all contacts of the cam switches S23 and S24 are closed, errors in monitoring and restarting the equipment will be automatically recognized and cause the motor protection switch Q1 to release. If an error occurs in identifying the various positions of the load converter, the two monitoring loops will either be electrically active, or will be inactive; both cases will cause the motor protection switch Q1 to release.

Claims (1)

1. the load tap changer that has a motor driver; be used for carrying out continual conversion between each tapping at an adjustable transformer under the on-load situation; wherein be provided with one and be used for selector and load transducer of under the on-load situation, carrying out actual converted that new tapping is selected on non-loaded ground in advance; wherein selector and load transducer are handled by a coupling bar of motor driver jointly; so that motor driver is controlled the selection driver of selector on the one hand; pull-up is carried out the follow-up power memory of controlling to load transducer on the other hand; wherein motor driver has a motor; this motor can be activated by means of a motor protecter respectively according to different direction of rotation; and in the circuit of this motor, be provided with an electric motor protecting relay; it is characterized in that

On load transducer, be provided with inductive range sensor (S70, S71), each position of this sensor load transducer;

On coupling bar, be provided with one with the cam track of direction of rotation related work and two and the corresponding cam switch of this cam track (S23, S24);

In the cam track of selecting directly to be provided with on the driver another one and irrelevant to rotation direction work, this cam track is corresponding to other the 3rd cam switch (S13);

And be provided with and be used for range sensor (S70; S71), described two cam switch (S23; S24) and the electric device that compares of the actual switch position that obtains respectively of described other the 3rd cam switch (S13) and the load tap changer normal condition when at every turn operating; make when normal operating conditions has been departed from least one position of the switch in the above-mentioned actual switch position, can starter motor protection switch (Q1).

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