1 remote control status of catenary disconnector

At present, the remote control of catenary disconnector in high-speed railway is mainly in the form of optical fiber control, which is mainly developed from the concept of digital substation. Its main features are: (1) reducing the number of indoor and outdoor control cables, thus reducing the harm of external reasons such as lightning and electromagnetism to internal equipment; (2) The control signal is transmitted through the optical cable, which reduces the interference. At the same time, this form of control has also brought new problems, mainly reflected in:

①RTU and other electronic components are placed in the outdoor control box, which leads to poor operating environment and increased component damage rate.

(2) Control loop, logical judgment, etc. It becomes complicated and links increase, which leads to the increase of uncertain factors such as false display of signals.

(3) (3) RTU, operating mechanism control panel and other working power supplies are in the same circuit. When the power supply voltage is unstable, the unstable factors of each link increase.

According to incomplete statistics, since the opening of the high-speed railway, * * * has failed 10 for more than 30 times, and the switch position has been displayed incorrectly 100 for more than 30 times. Although it has been rectified many times, the symptoms are not cured, problems and hidden dangers still exist, and the problems have not been fundamentally solved.

2 Cause analysis

2. 1 The reasons for misoperation of the disconnector of catenary are as follows.

(1) The signal connection between RTU and the operating mechanism is disturbed, which mistakenly triggers the self-holding loop of the operating mechanism, resulting in misoperation of the switch. It is found that the interference signal does exist, especially when the catenary fails. For example, after the misoperation of the OCS disconnector occurs in the East Ring Road of Hainan, the OCS work area and relevant personnel shall conduct on-site measurement. After the external 220 V power supply stopped, the voltage of 40 ~ 90 V was still measured on this connecting line.

It is worth noting that there is still a hidden danger in the connection between the disconnector operating mechanism and RTU. If the 220 V power supply is connected with the ground wire reversely, the RTU outlet relay may break the zero line, which is more hidden. In bad weather, if the insulation of the connecting wire is reduced or grounded instantly, it will directly lead to the wrong operation instruction.

During transportation, the heating circuit in the operating mechanism of catenary disconnector often reports abnormal operation; In Dezhou, Xuzhou, Zhengzhou and other places of Beijing-Shanghai high-speed railway, when the catenary fails, the air switch in the disconnector operating mechanism trips. This proves from another side that the induced voltage (current) does exist, but it interferes with different circuits.

(2) The outlet control relay of the operating mechanism is out of order, and the dispatching desk can't operate after issuing the command, but the operating command is saved inside the operating mechanism. In the subsequent operation, the outlet relay may be restored, and the operation command will act immediately, resulting in the switch action.

(The IP address of RTU conflicts, causing another switch to fail when operating the switch. This phenomenon mostly happens after the new replacement of RTU, which is caused by the carelessness of the replacement personnel.

(4) The operating button of the control panel of the catenary disconnector and the PLC send commands by mistake. This kind of fault happened in Wuhan-Guangzhou section of Beijing-Guangzhou high-speed railway, and it happened three times, which has been solved after delay treatment.

2.2 Reasons for the refusal of the OCS disconnector (1) The air switch in the disconnector operating mechanism tripped.

A 1, A2, B 1, B2, any switch trips, which will cause the disconnector of catenary to refuse to operate. B 1 switch is the most frequently tripped switch in operation, and this phenomenon mostly occurs during the catenary fault.

(2) Electronic components are damaged.

(3) The transmission channel is interrupted.

2.3 Reasons for the display error of position signal of catenary disconnector

During the operation of (1), it is found that the automatic switch of traction substation is easy to send remote signals by mistake when the main and standby channels are switched, which leads to the display error of dispatching console.

(2) The circuit board of RTU or operating mechanism is disturbed and the display is incorrect.

(3) Control circuit components are damaged.

The wrong display will cause the dispatcher to be at a loss. For example, during the operation of Zhengzhou-Xi 'an high-speed railway, the OCS phase separation switch shows closing, and the dispatcher immediately pulls the switch, but the switch cannot be pulled after the display operation is overtime. After 6 minutes, the switch automatically turns on again. So far, it is not known whether the switch really acts or displays an error.

3 solutions

The basic guiding ideology to solve the problems of misoperation, refusal to operate and display error of catenary disconnector is to eliminate interference and strengthen control, so that even if there is interference, there will be no misoperation. There is no other good way to eliminate interference except standard construction and grounding, so it is mainly to strengthen control.

3. 1 Prevent misoperation of catenary disconnector.

There are three main measures to prevent misoperation under the existing control mode of high-speed rail catenary disconnector: first, learn from the advantages of cable direct control mode, disconnect the operating power supply without operation, and realize the dual control of motor control loop; The second is the dual-port output of control commands; The third is the delayed release of the self-holding function of the operating motor circuit.

The operating mechanism box controls the motor circuit air switch B 1 Add a remote control operating mechanism to realize remote control operation, and turn off the switch when it is not in operation. Cancel switches A2 and B2.

The switch is connected in series with the control command outlet contactor, which plays a dual control role in the motor circuit, greatly reducing the probability of misoperation caused by interference signals.

The RTU outlet relay is changed to double nodes, and the live wire and ground wire of the 220 V control command are disconnected at the same time. Compared with single-port output, dual-port output reduces the probability of misoperation caused by interference.

Regularly release the self-holding function of the locking relay in the operating mechanism box to avoid immobility during operation and misoperation when there is no operation.

3.2 Measures to prevent the disconnector of catenary from refusing to operate

Adding remote control of operating mechanism to switch B 1 not only eliminates misoperation, but also achieves the effect of killing two birds with one stone. Switches A2 and B2 are cancelled, and switch B 1 is normally in the off state, so it is no longer tripped. All low-pressure air switches shall be equipped with auxiliary contacts, and position signals shall be transmitted to the dispatching desk.

3.3 Measures to Prevent Incorrect Display of Switch Position

(1) The monitoring screen of the OCS disconnector is directly connected with SCADA, without the integrated automatic switch.

(RTU and the control module of the operating mechanism give an alarm during the self-inspection. When the module can't work normally, it will give an alarm to the dispatching desk. At this point, all remote information of the switch action will be ignored.

(3) When the B 1 switch is in the off state, the operating power supply is not connected, and the action signal of the catenary disconnector in this process can generally be judged as an error message and ignored. At the same time, it strengthens the dispatcher's method to judge whether the catenary disconnector is misoperation or misoperation.

4 conclusion

(1) This paper analyzes the causes of misoperation, refusal to operate and non-display of the disconnector of catenary under the optical fiber control mode, and puts forward some improvement measures for reference of designers.

(2) The problems existing in the remote control of catenary disconnector also show that the two forms of optical fiber control and cable direct control have their own advantages and disadvantages, and they should learn from each other, learn from each other's strengths and make up for each other's shortcomings, and gradually improve them. The remote control of catenary disconnector needs system design, and can't completely rely on the simple superposition of products from different manufacturers.

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