Simulation Analysis of Vehicle Body Overvoltage Caused by EMU

Operating Main Circuit Breaker based on 3D Vehicle Body Modeling

An Zhang

1, a

, Qingpeng Feng

1, b

, Jianqiong Zhang

2, c

, Zhongkang Yuan

2, d

, Qingfeng Wang

2, e

CRRC Qingdao Sifang Co., Ltd, Qingdao 266000, China;

Southwest Jiaotong University Chengdu 610031, China.

wangqingfeng173@163.com

Keywords: Three-dimensional body model; overvoltage of bullet car body; operating main circuit breaker; EMU.

Abstract: At present, China's high-speed railway is in the process of rapid development, followed by the safety of emu

has attracted increasing attention. In the course of emu running, the main circuit breaker will be frequently

operated in the process of excessive phase, lifting bow and so on, thus causing transient overvoltage.

However, the shielding layer of the high-voltage cable is connected to the vehicle body, which will make

the over-voltage coupling to the vehicle body, forming the over-voltage of the vehicle body and

endangering the driving safety. In this paper, based on the three-dimensional vehicle body model and based

on the analysis of the overvoltage generation principle of the vehicle body, the electromagnetic interference

coupling path is obtained. Considering the actual working conditions of the standard emu, the interference

signal caused by the disconnection of VCB is taken as the interference source to analyze the over-voltage

distribution of the vehicle body caused by the disconnection of VCB. The actual three-dimensional model of

the vehicle body and the high-voltage cable is built and embedded into the circuit module, which breaks the

traditional equivalent method of equating the vehicle body with the four-side impedance, and the over-

voltage characteristics of the vehicle body at a specific position can be obtained. The simulation results

show that the generated overvoltage is about 2.9kv, the oscillation time is about 25us, and the frequency

spectrum is mainly 1.62MHz, which conforms to the basic characteristics of overvoltage.

1 INTRODUCTION

Nowadays, the safe operation of high-speed emu is

facing more and more challenges from the external

environment. The safe operation of emu has also

attracted wide attention from scholars. Frequent

operation of the main circuit breaker in the process

of over phase, lifting bow and short circuit fault of

high-speed emu will cause transient overvoltage,

which will not only accelerate the insulation aging

of the high voltage components on the roof or even

break down the insulation, but also affect the normal

operation of the on-board electronic equipment,

damage the emu train operation safety.

The domestic and foreign scholars' research on

the operation overvoltage of circuit breakers mainly

focuses on the power system with different voltage

levels. The research on the operation overvoltage of

high-speed emu circuit breakers generated by the

operation of on-board circuit breakers in the process

of over phase, bow lifting and short circuit fault is

still relatively rare. Wan Yusu built the whole

traction power supply circuit of "traction substation -

- catenary network -- high-speed emu", introduced

the mechanism of operating overvoltage during the

operation of the circuit breaker, and finally

simulated the over-voltage waveform of the vehicle

body caused by the operation of the circuit breaker

(Wan Yusu, 2017). Satoru Hatsukade of the Japan

railway technology research institute has analyzed

the causes of overvoltage on the vehicle body,

arguing that excessive overvoltage on the vehicle

body will cause the failure and damage of on-board

equipment, especially on-board electronic equipment

(HATSUKADE S, MAEDA, 2005). Ding Yong

analyzed the characteristics of operating overvoltage

of on-board vacuum circuit breakers in high-speed

emu, and built a simulation model based on the

electrical structure of a certain emu. Finally, the

consistency of simulation results and test results was

compared (DING Yong, 2017). Yan Jiabin analyzed

the electromagnetic interference problem of the

Zhang, A., Feng, Q., Zhang, J., Yuan, Z. and Wang, Q.

Simulation Analysis of Vehicle Body Overvoltage Caused by EMU Operating Main Circuit Breaker based on 3D Vehicle Body Modeling.

DOI: 10.5220/0010057400570063

In Proceedings of the International Symposium on Frontiers of Intelligent Transport System (FITS 2020), pages 57-63

ISBN: 978-989-758-465-7

speed sensor and believed that the surge overvoltage

of the vehicle body would be coupled to the core

wire through the parasitic capacitance between the

shield layer and the core wire, thus causing

interference to the speed signal transmitted in the

core wire of the speed sensor (Yan Jiabin, Zhu Feng,

Li Jun, Sha Miao, 2015).

Most of the predecessors used the circuit to

model the over-voltage simulation model of the

vehicle body, equating the high-voltage cable with

the distributed parameter model and the vehicle

body with a four-side impedance. However, the

interference of the vehicle body at a specific point

cannot be accurately reflected.

Based on the analysis of the overvoltage

generation principle of the vehicle body, the

electromagnetic interference coupling path is

obtained. Considering the actual working conditions

of the emu, the three-dimensional model of the

vehicle body was established based on the wiring

conditions of the high-voltage cable, and the

interference signal caused by the breaking of VCB

was used as the interference source to analyze the

over-voltage distribution of the vehicle body caused

by this interference source. The actual car body

model is adopted and the 3d model is embedded in

the circuit module, which breaks the traditional

equivalent method of equating the car body with the

four-side impedance, and the over-voltage

characteristics of the car body at a specific position

can be obtained. The analysis and prediction of the

over-voltage performance of the emus are realized to

ensure the safety of the emus.

2 BASIC PRINCIPLE AND

SIMULATION MODEL

BUILDING

2.1 Principle of Generating

Overvoltage of Vehicle Body by

Disconnecting VCB Operation

Before the circuit breaker operates in normal

working condition, the traction motor is no longer

working, that is, the traction transformer is in no-

load state. Therefore, the process of disconnecting

the circuit breaker is similar to a common operation

of removing no-load transformer in the power

system. To cut off the no-load transformer is to cut

off the small current of an inductive load, the current

value is very small, at this time the circuit breaker's

arc extinguishing ability will play to the extreme, so

that the no-load current is truncated before 0, which

is the so-called blocking phenomenon, at this time

will produce a very high overvoltage. While the

shielding layer of the high-voltage cable is

connected to the car body, the over-voltage will be

coupled to the shielding layer of the high-voltage

cable through the core wire, and then transferred to

the car body, causing the over-voltage on the car

body. (Luigi Battistelli, et.al, 2011)

As shown in figure 1, this is the overvoltage

equivalent circuit schematic diagram of high-speed

emu operating circuit breaker. The circuit breaker is

equivalent with switch K1, where US is the traction

substation supply voltage. Catenary is equivalent in

terms of centralized parameters. The resistance and

inductance of catenary conductor are RS

respectively, LS represents. The excitation

inductance of the traction transformer is Lm, and CT

is the equivalent distributed capacitance of the high-

voltage cable core to the vehicle body. In general,

CT value is very small.

Figure 1: Operation circuit breaker overvoltage equivalent

circuit diagram.

When switch K

is opened, assuming the current

value is I

before the zero crossing of L

, then the

voltage value at both ends of the equivalent

capacitor C

is U

. After the current is truncated, the

LC circuit will have high-frequency oscillation. Self-

oscillation frequency is .

Since the C

value is small, when all the

magnetic field energy is converted into electric field

energy instantaneously, the capacitor C

will have a

large overvoltage. The circuit equation is as follows:

(1)

The initial condition is ,

by solving the above equation:





Cudt

dt L

dt L C









)0( ,)0( UuIi





FITS 2020 - International Symposium on Frontiers of Intelligent Transport System

(2)

The maximum over-voltage amplitude at both

ends of the equivalent capacitance to earth is:

(3)

According to the above equation, the maximum

overvoltage at both ends of the equivalent

capacitance to earth is related to the closure phase

Angle and the high-frequency oscillation frequency.

When the phase Angle is 0° and 180°, the minimum

over-voltage amplitude of the circuit breaker when it

is opened is Um; When the phase Angle is 90° and

270°, the amplitude is the largest, and the maximum

operating overvoltage is Um f0 /f. Among them, the

high-frequency oscillation frequency f0 is related to

the electrical parameters of traction transformer and

high-voltage cable. (David D. Shipp, et.al, 2012)

2.2 Model Building

The model can be modeled from six modules

including traction substation, catenary, high-voltage

system, vehicle body, high-voltage cable and

connection model. After the circuit model modeling

is completed, the high-voltage cable and vehicle

body can be connected to the circuit to complete the

construction of the overall model.

(1) Traction substation

Traction substation, as a connection between the

power system and the traction network of electrified

railway, functions to convert the power supplied by

the power system into the power suitable for electric

traction and its power supply mode, among which

the core equipment is the traction transformer in the

substation. In practical calculation, the traction

substation can be equivalent to a power supply with

internal impedance, as shown in figure 2.The size of

each parameter is:

(4)

Figure 2: equivalent model of traction substation.

(2) Catenary

As the train's special working condition usually

occurs in the bullet train station or station, which is

far from the traction substation, the length of the

taking-power arm is 25km.According to the typical

parameters of the traction network, set the catenary

wire resistance value is 4.45 Ω, inductance value is

35.7 mH, the capacitance between rail is 0.1342 u F,

rail backflow resistance value is 1.0125 Ω, reflux

inductance value is 3.24 mH, equivalent model is

shown in figure 3.

Figure 3: Equivalent model of traction network.

(3) Grounding module

In this model, each vehicle's protective

grounding circuit is equivalent to two protective

grounding circuits at the front and rear of the

vehicle. The impedance between each connection

point is calculated by the unit resistance and the unit

inductance of the rail. The overall equivalent circuit

diagram is shown in figure 4. The circuit in the black

box represents 3 cars' protective grounding, while

the circuit in the red box represents 3 cars' working

grounding. The parameter values are arranged as

shown in table 1.

tUt

0000

cossin







sincos

IUU



U =38.89sin100

R =0.165Ω

L=10.8mH



；

Simulation Analysis of Vehicle Body Overvoltage Caused by EMU Operating Main Circuit Breaker based on 3D Vehicle Body Modeling

Figure 4: Schematic diagram of ground circuit.

Figure 5: Schematic diagram of the model.

Table 1: Grounding parameter values.

Parameters to describe Parameter value

Protective ground resistance 0.11Ω

Protective ground inductance 8.6uH

Working ground resistance 6.5mΩ

Based on the above judgment, the overvoltage

model of vehicle body was established. As the high-

voltage cables are distributed in 3-6 vehicles, the

simulation diagram of 3-6 vehicles is presented as

follows.

This model uses Q3D and Simplorer under

ANSYS platform to conduct solid modeling of the

high-voltage cable and vehicle body model, obtain

the distribution parameters between each part, then

import them into Simplorer for circuit connection,

and preliminarily obtain the over-voltage simulation

results.

2.3 Three-dimensional Modeling of

Vehicle Body ad High-Voltage

Cable

The simplified model of the car body ignores the

parts that have little influence on the overvoltage,

such as the seat, inner assembly and small parts. In

order to obtain the impedance parameters of each car

body, ports are set on the roof and bottom of each

car to represent the current inflow and outflow,

respectively. The schematic diagram of the model is

shown in figure 6.

Figure 6: Vehicle body setting.

FITS 2020 - International Symposium on Frontiers of Intelligent Transport System

The inner and outer conductors are drawn

according to the actual size of the high-voltage cable

and the actual wiring condition, and the influence of

the medium layer is ignored. The specific model is

shown in figure 7 and figure 8.The inner and outer

conductors are set as current paths respectively.

Figure 7: Distribution of high-voltage cables.

Figure 8: Section of high pressure cable.

After the simulation in Q3D software is

completed, the distributed parameter results of the

model can be obtained by taking three vehicles as an

example, as shown in the figure below.

After encapsulating the Q3D model, import it

into circuit simulation software Simplorer, as shown

in figure 10. This module has taken into account the

influence of distribution parameters. Each port on

the module, namely the port set in Q3D, can be

connected to the circuit through the port.

Figure 9: Distribution parameter matrix.

Figure 10: Q3D packaging module.

2.4 Overall Model Building

According to the above mentioned traction

substation, catenary, high-voltage system, vehicle

body and grounding system model, connect the

high-voltage cable to the vehicle body circuit.

Figure 11: Overall simulation model.

Simulation Analysis of Vehicle Body Overvoltage Caused by EMU Operating Main Circuit Breaker based on 3D Vehicle Body Modeling

Details are as follows: the body port diagram is

shown in figure 12. The bottom of each car is

grounded through the grounding impedance, and the

workshop connection wire is connected through the

resistance.

Figure 12: Vehicle body port connection diagram.

3 ANALYSIS OF SIMULATION

RESULTS

The simulation setting is VCB shutdown at 5ms. The

simulation results of overvoltage of 3 vehicles are

shown in figure 14. The generated overvoltage is

around 2.9kv, the oscillation time is around 25us,

and the main spectrum is 1.62MHz.The basic

characteristics of vehicle body overvoltage are: the

amplitude is between 3kV and 5kV; he oscillation

time is tens of microseconds. The main frequency

distribution is 1MHz-2MHz. (Wan Yusu, 2017)

Through the establishment of vehicle body and cable

entity model, import circuit software to replace part

of the structure of the existing overvoltage circuit

model, after the simulation, the overvoltage time

domain waveform and frequency domain waveform

are obtained, and the analysis of the waveform

conforms to the characteristics of the typical

overvoltage waveform, which can demonstrate the

correctness of the model.

Figure 13: Vehicle body overvoltage waveform.

Figure 14: Duration of overvoltage of vehicle body.

FITS 2020 - International Symposium on Frontiers of Intelligent Transport System

Figure 15. Spectrum of overvoltage of vehicle body.

4 SUMMARY

Based on the three-dimensional vehicle body model,

this paper carried out the simulation modeling

analysis on the over-voltage of the vehicle body

caused by the main circuit breaker operated by

standard emu. The traditional equivalent method of

equating the body with the four-side impedance is

broken, and the over-voltage performance of the

body of emu is analyzed and predicted.

Based on the modeling method proposed in this

paper, the obtained vehicle body overvoltage is

around 2.9kv, the oscillation time is around 25us,

and the spectrum is mainly 1.62mhz, which

conforms to the basic characteristics of overvoltage.

Therefore, the simulation modeling method

proposed in this paper can simulate and analyze the

overvoltage of the vehicle body caused by the

operation of the main circuit breaker, and realize the

analysis and prediction of the overvoltage

performance of the emu body, so as to guarantee the

safety of electromagnetic compatibility of the emu.

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Simulation Analysis of Vehicle Body Overvoltage Caused by EMU Operating Main Circuit Breaker based on 3D Vehicle Body Modeling