Application of Hall-type sensors in subway power monitoring

Ren Yunye Jiangsu Ankerui Electric Appliance Manufacturing Co.
, Ltd.
Jiangyin, Jiangsu 202206【Abstract】This paper briefly introduces the subway power monitoring system, as well as the working principle of closed-loop Hall current sensor and Hall voltage sensor based on Hall effect, and confirms the application of Hall-type sensors in power monitoring systems and Hall-type sensors in power monitoring system applications
.

【Keywords】Subway, power monitoring system, Hall-type sensor, closed-loop Introduction With the progress of urbanization in China and the increasing congestion of urban traffic, subway traffic has become an important means
of transportation in modern cities.

In recent years, China has accelerated the pace
of development of subway transportation.

At present, the integrated automation system is widely used in subway traffic, including power monitoring system, fire alarm system, automatic ticket sales and inspection system, access control system, mechanical and electrical equipment monitoring system, etc
.

The power monitoring system is an important part of the subway traffic comprehensive monitoring system, which is mainly a real-time remote monitoring of various equipment on the subway traffic contact network, through the measurement, comparison and calculation of various power parameters, real-time feedback is reported to the system, so that the system can deal with various accidents and alarm events
according to the feedback information.

The schematic diagram of the subway power monitoring system is shown in
Figure 1.

Figure 1 The power parameters detected and measured by the subway power monitoring system are mainly the current and voltage
of each main loop.

Traditional current measurement is to convert the current into voltage through the sense resistor, which has two problems: the sense resistor consumes energy and reduces the efficiency when the high current is sensed; The sense current is not isolated from
the output voltage.

Traditional voltage detection also has the problem
that the sense voltage is not isolated from the output voltage.

Hall-type sensors have been widely used
in current and voltage measurement due to their small size, low noise, low power consumption, and good isolation.

First, the application of Hall-type sensor in power monitoring system 1.
The working principle of Hall-type sensor Hall-type sensor is mainly suitable for the isolation conversion of complex signals such as AC, DC, pulse, etc.
, through the Hall effect principle, the transformed signal can be directly collected by various acquisition devices such as DCS, AD, DSP, PLC, secondary instruments, etc.
, with fast response time, wide current measurement range and high precision, strong overload capacity, good linearity, strong anti-interference ability and other advantages
.

2.
Technical parameters of closed-loop Hall sensor 3.
Hall current, voltage sensor access to the power monitoring system Hall current and voltage sensors can be applied in all aspects of the power monitoring system and each subsystem, as shown in
Figure 1.

High-voltage measurement and control protection device can choose to use Hall voltage sensor measurement and feedback according to the amplitude of the voltage, Hall voltage sensor can measure up to thousands of volts of DC or AC voltage, and can output a few tens of milliamps or several volts of voltage according to demand for feedback
signals.

Its accuracy can be achieved better than 1%, linearity is better than 0.
2%, and reaction time is less than 10μs
.

Medium-voltage and low-voltage measurement and control protection devices can use Hall current sensors to measure and feedback, Hall current sensors can measure DC or AC currents up to thousands of amperes, and can output a current of less than 200mA or a few volts for feedback signals
.

The accuracy of Hall current sensors can be better than 1% or even lower, especially the accuracy of high-current sensors can be better than 1‰, linearity is better than 0.
2%, and reaction time is less than 10μs
.

4.
Hall current, voltage sensor application needs to pay attention to the problem (1) should be based on the size of the measured current reasonable selection of wire or bus strip, and then choose the appropriate aperture of the current sensor, the bus strip can fill the sensor aperture or in the center of the aperture position
.

(2) When the sensor is tested, the power supply should be turned on first, and then the test power supply
should be turned on.

When shutting down, the power supply under test should be turned off first, and then the power supply should be turned off to demagnetize the sensor
.

(3) Hall-type sensors should be installed as far away from the strong magnetic field position as possible, such as should be kept away from
transformers, large inductors, large current bus bars, etc.

(4) When using Hall voltage sensors, attention should be paid to the withstand voltage and power consumption of the current-limiting resistor, so as to avoid damage
to the resistors due to over-limit stress.

5.
Hall current sensor selection specifications and parameters compared to Table II, ConclusionThis paper introduces the application of Hall current and voltage sensors in subway power monitoring systems, and prompts the problems
that should be paid attention to in the application process.

It is clear that Hall sensors have a wide range of applications
in the detection and measurement process of subway power monitoring systems.

About author:Ren Yunye, currently working in Jiangsu Ankerui Electric Appliance Manufacturing Co.
, Ltd.
, mainly from the research and development and application
of power sensor products.