Instrumentation & Measurement Magazine 26-2 - 5

Fig. 2. The structure of the high-speed train (from [3], ©2021 IEEE).
three-phase ac (100 kV/50 Hz) provided by the power station
into the single-phase ac (27.5 kV/50 Hz), and then transmits it
to the catenary. Secondly, the pantograph of the train contacts
with the catenary and slides on it, so that the train can obtain
electric energy. Thirdly, the transformer transforms the voltage
and frequency of the electric energy and transmits it to the motor.
Finally, the motor drives the wheels to rotate to make the
train run. At the same time, the current flows back from the rail
to the traction substation to form a power supply circuit.
The typical high-speed train in China is mainly composed
of 16 carriages, four pantographs, four working earthings, and
one protective earthing. As shown in Fig. 2, 01TB~16TB are the
serial numbers of the carriages, in which the pantographs and
working earthings are located at 02TB, 07TB, 10TB, and 15TB,
respectively, and the protective earthing is located between
08TB and 09TB [14].
Analysis and Calculation of the Electrical
Parameters
As shown in Fig. 3, the catenary can be simplified into a circuit
model with two circuits. The one is composed of the power
supply line and earth (Circuit 1), and the other one is composed
of the rail and earth (Circuit 2). Where z1
, z2, and z12
are
the self-impedance and mutual-impedance of the Circuit 1 and
Circuit 2, respectively, I and It
current in the rail, and D0
are the traction current and the
is the distance between the train and
the traction substation.
The parameters of the catenary and rail used in the typical
high-speed electrified railway are listed in Table 1. The
equivalent impedance per unit length of catenary z can be calculated
by combining with Carson theory [15], circuit theory,
Fig. 3, and Table 1:
U U z
zz j
DI
2
=
1 
2  
1
12 =0.176+ 0.5768 mΩ/m.
02
z
According to the actual test results and the calculation
method of rated voltage and current [16], the relevant parameters
of the high-speed train transformer and TBs can be
obtained, as listed in Table 2.
Comprehensive Model of the HighSpeed
Train
Establishment of the Train Models in Different
Sections
Firstly, when the train passes through the common section of
the power supply line, the pantograph will leave the catenary
instantaneously due to the mechanical vibration, uneven line,
and other reasons. Based on the actual situation of the highspeed
railway system, a simplified model of the train passing
through the common section is established, as shown in Fig. 4.
The model includes the following five parts:
◗ Part ① is the distributed parameter model of the secondary
side of the traction substation where us
voltage (uS(t)=27500cos(314t)V), and the values of Rs
(t) is the
and
Ls are listed in Table 2.
◗ Part ② is the distributed parameter model of the catenary,
whose range is from the traction substation to the position
where the PCA occurs. C'J
length between the catenary and earth, and C " J and L " J
is the capacitance per unit
are
the capacitance and inductance per unit length between
the catenary and train roof. They can be calculated by
Table 1 and (1).
◗ Part ③ is the distributed parameter model of the sixteen
TBs, where the values of RT
and LT
are listed in Table 2.
◗ Part ④ is the distributed parameter model of the catenary,
whose range is from the position where the PCA occurs to
the neutral section.
Fig. 3. The current circuit of catenary.
April 2023
◗ Part ⑤ is the neutral section, where the pantograph is
completely disconnected from the catenary, so the resistance
R∞
is infinite.
IEEE Instrumentation & Measurement Magazine
5
(1)
Instrumentation & Measurement Magazine 26-2

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