Instrumentation & Measurement Magazine 26-2 - 10

Table 4 - Maximum values of the transient current and voltage
Test Value
Simulation Value
Position
Common Section
Neutral Section
current
185 A
365 A
voltage
19.5 kV
30.6 kV
current
170 A
350 A
high-frequency component of the transient voltage and
current.
◗ The peak value and high-frequency component of the
transient voltage and current of EMI will increase significantly
with the train speed, and the increase of the
high-frequency component will increase the intensity
of its radiation. Therefore, the faster the train speed, the
more serious the EMI.
Critical Factors in the Model
Establishment
Some key factors need to be paid attention to when establishing
the model.
Critical Factors for the Electrical Parameters
The electrical parameters of key parts of the high-speed train
are necessary to accurately establish the train model. The specific
parameters should include the relevant parameters of the
catenary, traction transformer, and carriages. Therefore, the
following parameters need to be measured repeatedly and calculated
accurately:
◗ Power supply mode and voltage level of the substation
to the train.
◗ Electrical parameters of the catenary, including resistance,
permeability, conductivity, equivalent impedance,
etc.
◗ Electrical parameters of the transformer, including
capacity, voltage, current, resistance, impedance, and
inductance.
◗ Dimensions and electrical parameters of the train bodies
and steel rail.
Critical Factors for Train Model Establishment
◗ Clarifying the situation of the train in two different
sections (the common section and the neutral section) in
advance to determine the different position of the PCA in
the two train models.
◗ The train model in the neutral section includes the neutral
line. Therefore, it is necessary to accurately add the position
and parameters of the neutral line.
◗ Using the Bergeron numerical algorithm to solve the
distributed parameter model of the train. In this process,
the Bergeron equivalent circuit model should be established
correctly.
Critical factors for Improving the PCA Model
The existing PCA model assumes that the arc voltage and dissipative
power are constant, which is inconsistent with the
10
voltage
19 kV
29 kV
current
8.11%
4.11%
voltage
2.56%
5.23%
actual situation of the PCA. Therefore, the PCA model needs to
be improved, and its critical factors are as follows:
◗ Fitting the relationship between the PCA voltage and
train speed correctly by using the actual measurement
results.
◗ Discriminating the dissipative power and length of the
PCA in the two sections to establish the different PCA
models.
Main Issues in the Extended Application
The comprehensive model proposed in this paper has been
well-verified on typical high-speed trains in China. Because
the model and modelling method are universal, it can be extended
to other types of trains. However, we need to pay
attention to some differences and issues when expanding the
application.
Applied to Different Types of Trains
Trains with different number of carriages have different
overall structures and related parameters. This paper only
considers the Chinese train with 16 carriages as an example for
modelling. However, the number of carriages of other types
of trains is different, for example, some trains have only eight
carriages (Japanese and German trains) or four carriages (Brazilian
trains). When this modelling method is applied to other
types of trains, the following differences should be noted:
◗ Actual dimensions and relevant electrical parameters of
the trains.
◗ Specific location of the grounding system and its
impedance.
◗ Current return through the grounding system and rail.
Applied to Varied Operation Environment of
Trains
The running environment of trains will affect the characteristics
of the PCA. For instance, the formation probability of
PCA is related to the degree of vibration of the train running
route, and the radiation characteristics of PCA are related to
the humidity of the surrounding air. Therefore, it is necessary
to consider environmental factors when modelling the
PCA.
Applied to the Train with Different Speed Limits
High-speed trains with different speed limits have corresponding
levels of power supply, pantograph, catenary, and
rail. Therefore, it is necessary to adjust the relevant parameters
when applying this model to trains with different speed
limits.
IEEE Instrumentation & Measurement Magazine
April 2023
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