1.The electrical equipments needed in railway running.
The voltage coverage of railway electrical equipment is wide, ranging from 110kV/220kV traction voltage to 0.4kV low-voltage systems, and the equipment is also different. Therefore, the types of current transformers required to measure the voltage of these devices are also different:
1.1. Medium-voltage switch cabinets/circuit breakers (6kV - 35kV).
In the railway power supply system, medium-voltage switch cabinets and circuit breakers (6-35kV) mainly undertake the functions of receiving and distributing power sources, controlling and protecting circuits, as well as ensuring safe operation. They introduce current from the public power grid to supply power for the station's operation and provide current protection when there is a short circuit due to excessive current. Through isolation and interlocking functions, the medium-voltage switch can also achieve safe operation and maintenance isolation of busbars and outgoing lines, reducing the risk of misoperation and equipment damage. Meanwhile, modern medium-voltage switch cabinets are mostly equipped with intelligent monitoring and communication interfaces, which can collect the operating status in real time and be connected to the dispatching and operation and maintenance platform to achieve intelligent monitoring of power operation. In this kind of equipment, it is more suitable to use epoxy casting type current transformers to detect the current.
1.2. Low-voltage distribution cabinet (AC 0.4kV)
Low-voltage distribution cabinets (AC 0.4kV) are usually installed inside stations or at the end of train lines. Their main function is to collect and distribute the power reduced by transformers to various branch lines, complete short-circuit/overload protection, metering and monitoring, backup power switching and power quality management, and ensure the safe, continuous and visual operation of critical loads. It is more suitable for the measurement of current transformers without power-off, such as LMZK, DP or HK current transformer.
1.3. Digital Power Distribution System (EDCS)
The Digital Power Distribution System (EDCS) significantly enhances the power supply reliability and operation and maintenance efficiency of railway stations by connecting power distribution equipment to the cloud and interconnecting it with SCADA/BMS, enabling real-time visualization of status, abnormal early warning and remote control, energy consumption and power quality analysis, as well as condition-based predictive maintenance. It is more suitable to measure with a Roche coil.
2.Application and Advantages of Transformers in the Above-mentioned Equipment
2.1 FRC Rogowski coil transformer:
The Rogowski coil adopts the principle of external vortex current to detect objects. It consists of a closed helical electrode ring, wound with one or more copper wires, and inside it there is a series of electrical activities called "Roche notch waves". It is a coreless transformer whose size can be customized according to the customer's requirements.
2.2 Railway Medium-voltage switch cabinet current transformer LMZK 0.2 grade 1A/5A Epoxy casting：
Our LMZK series transformers comply with the national standards GB20840.1/GB20840.2, offering dual precision grades such as 0.2s/0.5s high-precision measurement grade and 10P5/10P10 protection grade. They support secondary current output of 5A or 1A It has an anti-pollution grade of Class II and a temperature tolerance range of -5 ℃ to 40℃. It combines high stability and applicability, and is widely used in the metering and protection of low-voltage distribution cabinets.
2.3 The 0.4kV low-voltage distribution cabinet renovation of the open-type DP current transformer does not require power-off installation of grade 0.5:
It adopts imported silicon steel sheet cores from Japan, UL-certified pure copper coils and red copper terminals, and is equipped with a new PC material 8.8mm thickened shell (laser serial number, ultrasonic welding) and environmentally friendly pearl cotton packaging. It supports plug-and-pull installation without power interruption, with high precision, stability and reliability, and is convenient for quick busbar modification. And it occupies a small area. It is a portable core balanced transformer.
2.4 The HK push-button split-type transformer can be quickly connected to SCADA/BMS predictive maintenance:
- It also adopts imported silicon steel sheets, UL-certified large-diameter pure copper coils, purple copper terminals and PC new material thickened shells (laser serial numbers, ultrasonic technology). It is installed with button opening and closing to achieve rapid and safe on-site connection. It is suitable for high-reliability incremental renovation and maintenance of low-voltage distribution, and is easy to install.
3.Installation method and schematic diagram
3.1. The process of installing LMZK transformers in medium-voltage distribution boxes: Select the single conductor to be tested in the low-voltage/secondary compartment of the medium-voltage switchgear → Install the LMZK in the direction of the current P1→P2 and lock and close it → Connect the secondary S1/S2 to the meter/relay protection/gateway (1A or 5A, check the secondary load and accuracy grade) → confirm that the secondary must not be open-circuited or short-circuited during maintenance, and the installation is completed.
3.2 Installation process of low-voltage distribution box Select the single phase line to be monitored in the distribution cabinet → Open and install the DP split-type CT in the current direction P1→ Clean and close the core, and confirm that the lock is in place → Secondary connect S1/S2 to the meter/relay protection/data acquisition terminal according to model 1A/5A Check the secondary load and polarity → Fix the beam wire and keep a safe distance from the live parts → Before closing the switch, confirm again that the secondary circuit of the CT must not be open-circuited.
4. Actual usage cases
Our transformers have been purchased and applied to the electrical equipment inspection of the Canadian metro and Busan Railway.
5.Contact way
If you want more information or support please contact us.
E-mail:bethy@heyiele.com Phone number:86-13968747975
