Adapted P45000 high voltage transducer as isolation barrier

On the current collector systems of certain locomotive series, proximity sensors verify the correct positioning of the contact shoe. Under adverse conditions, the sensors may come into contact with the third line. In such cases, this may lead to the destruction of the proximity sensors and to the transmission of the traction voltage to the rolling stock control system. Therefore, the sensor signal must be galvanically isolated from the analysis units.

Railroad tracks with special attention to the conductor rail and the "High voltage, danger to life" sign.

Key facts about the application

Sector

Railway | Rolling Stock

Application

Galvanic isolation of a sensor signal on a potential of 750 V

Measured Parameter

24 V signals for transmitting the collector position (galvanic isolation of 24 V switching signals against 750 V DC)

Main Requirements

Safe isolation of the sensor connection to the rolling stock control system with a system retrofit

Graphical representation of the application of Knick with a modified P45000 high-voltage transducer for the protection of personnel and vehicle control.

Description of application

For dual-mode locomotives with collector systems for conductor rails, the contact shoes are positioned underneath the conductor rails and pneumatically pressed against their lower surface to make contact. An inductive proximity switch (24 V) monitors the vertical contact shoe position and transmits the lowered or raised position to the rolling stock control system via a coupling relay.

Requirements for the application

Due to its position, contact between the proximity sensor and the conductor rail cannot be ruled out. To avoid risks to the locomotive personnel and damage to the train control system, the sensor signal must be galvanically isolated.

Why Knick ?
For the secured transmission of 24 V switching signals to the coupling relay, a high-voltage transducer in the P45000 series with basic isolation of up to 4800 V DC was adapted for signal transmission with switching characteristics.

In dual-mode locomotives, application-specific, adapted P45000 are used as isolation barriers between the control system and the current collector system

In railway networks that are only partially electrified or use different traction current systems, multi-system or dual-system rolling stock enables continuous line coverage without traction changes. While multi-system rolling stock can draw its traction current from different traction current systems, dual-system rolling stock has a bi-modal drive unit that is supplied from either diesel-electric power units or overhead lines. Dual-mode locomotives are a special form that have a contact system for conductor rails that run along the side of the line, alongside a generator with a diesel-electric drive.

Avoidance of Contact Between the Sensor and Conductor Rail with Potentially Serious Consequences

The collector systems of these locomotives position the contact shoes underneath the conductor rails and to make contact, press them against their lower surface via pneumatics. Inductive proximity switches (24 V) monitor the vertical contact shoe position and transmit the lowered or raised position to the rolling stock control system via a coupling relay. Since the proximity switches are located in the immediate vicinity of conductor rails with voltages of 750 V DC, under adverse conditions or in the case of mechanical defects, direct contact cannot be ruled out. Without an isolation barrier, a short circuit could not only destroy the proximity switch but in all likelihood could also destroy the coupling relay and the downstream control system. To limit the risk of damage to the proximity switches, one manufacturer looked for a simple, space-saving solution that could be integrated to protect the downstream electronics. With a P45000 high-voltage transducer adapted to the specific application, Knick was able to supply the ideal solution.

Solution

The high-voltage transducers in the P45000 series are certified in accordance with EN 50155 for use on rolling stock and designed to measure voltages between 500 V and 4500 V. In the present application, however, the transducers are only wired to galvanically isolate potentially destructive voltages between the proximity switches and the coupling relay. For the secured transmission of the 24 V switching signals to the coupling relay, Knick chose a P45000 design with an input measuring range for ±500 V and adapted the standard transmission behavior of ±500 V/±50 mA to signal transmission with switching characteristics. As the customer requested, Knick also replaced the bipolar 15/24 V power supply of the P45000 integrated as standard with a unipolar 24 V power supply. The solution has proven its worth. Thanks to the high basic isolation of up to 4800 V DC, test voltage resistance of 10 kV, and reinforced isolation of up to 2300 V DC between input, output, and auxiliary power, the high-voltage transducers in this application provide maximum protection for people and the control system. In addition, the high-voltage transducers met an important customer criterion for space-saving system integration with their slim design and housing width of only 28 mm.

Matching Products

P45000 High Voltage Transducer | Input up to ±3000 V overrange up to 150% | For use in SIL2 systems, redundantly in SIL3

Product number:

P45000

Related Industries and Applications

Railway

Electrical measurement in DC traction power substations and on rolling stock; conversion and duplication of speed sensor signals on-board rail vehicles.

High voltage and current measurement on rolling stock

Knick offers highly isolating transducers for measuring voltage and current. P45000 is the high-voltage transducer with the smallest footprint and SIL 2. It is used for direct current measurement on board all trains driven with direct and alternating current.

Speed signal doubling and conversion on rolling stock

P16800 makes it easy to retrofit rolling stock with control systems through the safe (SIL2/SIL4) conversion of speed sensor signals for odometry systems.

Railway Industry Brochure

Overview of railway-specific applications and product solutions

Blog Articles on this Subject

Sept 2024

Interface Technology

Hydrogen

Stack and String Voltage Measurement in Electrolyzers and Fuel Cells

Voltage, current and temperature measurement in electrolyzers with P40000 series high voltage transducers

Sept 2024

Interface Technology

New 30 mV Shunt Resistors for Knick Transducers

Knick is expanding the accessory range for its high-voltage transducers with immediate effect by adding shunt resistors with a 30 mV voltage drop

Sept 2024

Interface Technology

Exhibition, InnoTrans

Innovations at InnoTrans 2024 for rolling stock and DC traction power supply

At InnoTrans 2024 Knick presents electrical measurement solutions for rolling stock and DC traction power supply applications

Dec 2023

Company

|

Interface Technology

|

Process Analytics

Knick Austria - direct customer contact in Austria from 2024

Reorganization of sales in Austria and new contacts in the field of process analytics and interface technology

May 2022

Interface Technology

Energy

Energy storage - the handshake between renewable energy and electric vehicles

Energy storage technology such as battery and hydrogen are critical for growth and continuous development of renewable energy and e-mobility.

Feb 2022

Interface Technology

P52000VPD, Voltage

P52000VPD voltage presence detector reliably detects voltages up to 4200 V DC

The new P52000VPD voltage presence detector reliably monitors areas with high voltages and sends a signal to the downstream plant control system when a specified threshold value is reached.

Sept 2021

Interface Technology

USA, Exhibition

Knick Interface at Battery and Electric & Hybrid Vehicle Technology Expo

Knick will be showcasing high-voltage electrical measurement and signal conversion products.

May 2021

Interface Technology

Quadruple Standard Signals in Just One Signal Conditioner

The A20340 can output a standard input signal to four calibrated and galvanically isolated outputs in parallel.

Apr 2021

Interface Technology

Hydrogen

Electrical measurement and process analytics for hydrogen production

Knick products optimize hydrogen production in the process and in electrolyser operation.

Mar 2021

Interface Technology

High-Voltage Transducer, USA, P44000

Condition Monitoring of High-Voltage Motors

Having an active predictive maintenance campaign in place for large rotating equipment can be a key strategy for maximizing process uptime.

Mar 2021

Interface Technology

Pulse frequency conditioner for speed sensors

The new P16000 from Knick is a pulse frequency conditioner that converts frequency signals from speed sensors into standard signals.

Nov 2020

Interface Technology

High-Voltage Transducer, Voltage, P42000D2

Worldwide smallest transducer up to ±2200 V

The P40000 series from Knick enables reliable voltage measurements from ±50 mV to ±3600 V and current measurements from ±100 mA to ±20 kA.

Aug 2020

Interface Technology

DC

Importance of broad-range power supplies for DC electrical measurement

Many DC electrical measurement products manufactured by Knick contain universal, also known as broad-range, power supplies.

Jul 2020

Interface Technology

High-Voltage Transducer, DC, P29000

Measuring Photovoltaic Degradation

Photovoltaic (PV) array degradation is an important aspect to consider for system design and installation.

Jun 2020

Interface Technology

High-Voltage Transducer, USA

Electrical Measurement Solutions: Control from 480 to 4800 Volts

Voltage and current transducers from Knick bring true control to electrical measurement applications across a wide-range of industries.

Jun 2020

Interface Technology

High-Voltage Transducer

Benefits of High Voltage Transducers versus Instrument Transformers

When a need arises to step voltage in a circuit either up or down for purposes of power transmission or distribution, there is no doubt that transformers are essential.

Nov 2019

Interface Technology

DC, USA, Current

Shunt Resistor versus Hall Effect Technology

There are many systems where measurement of large DC currents are needed for performance and safety.

Mar 2018

Interface Technology

MTBF beyond 3000 years: A snap hook for your plant

Failure of equipment on the plant floor can lead to considerable and costly disruption.

Jan 2018

Interface Technology

UL

Knick Products Comply With UL - What Does That Mean?

There are different assessments and approaches to reach an adequate level of safety. Manufacturers are typically on the “safe” side, if they comply with recognized standards.

Nov 2017

Interface Technology

High-Voltage Transducer, P50000

High-voltage transducer offers more safety on railway vehicles

The requirements placed on railway vehicles have increased significantly in recent years. Products for rolling stock need to ensure a higher level of functional safety than ever before.

Feb 2017

Interface Technology

P41000TRMS