XL-CFL – BAUR cable fault location for long submarine & underground cables
Indispensable and robust, but sadly not indestructible: Long land and submarine cables for global power supply
Due to the growing demand for power and increasing dependence on renewable energy – more and
more of which is being generated offshore – submarine power cables are becoming indispensable for a reliable energy supply. Among experts, submarine cables are classified as critical infrastructure. Why critical? Firstly due to the harsh environment in which they are installed. Secondly – and this is also the most common cause of faults – submarine cables are exposed to mechanical stress, such as currents, fishing, or heavy ships' anchors, at irregular intervals and at all water depths, which can result in significant damage.
BAUR solutions for XL cable fault location
Suitable for all cable types:
- HVDC submarine cable links (monopole, bipole)
- HVDC land cable links
- AC submarine cable systems
- Combined AC land and submarine cable systems
BAUR XL-CFL – the advantages:
Security of supply as the top priority with your proven system for fast and efficient cable fault location
Since 2010, BAUR has been developing individual product solutions for fast and efficient fault location on long land and submarine cables. With the powerful systems and extensive expertise of BAUR specialists, critical cable faults on submarine cables have been located rapidly, efficiently, and precisely in recent years. You too can rely on BAUR expertise and the high-performance technologies that have been tried and tested worldwide.
Cable fault location outside the standard
What should you do when the favoured Time Domain Reflectometry method cannot be used?
The normal fault location methods Time Domain Reflectometry (TDR) in particular, but also the secondary/multiple impulse method (SIM/MIM) cannot always be used in very long cables (especially those with cross-bonding joints). One reason for this is that the measurement pulse or its reflection is too strongly damped over the long distance, making it very difficult to evaluate the pulse. Another possible cause is the high capacitance of the cable, which makes it difficult to achieve a usable pulse discharge with the SIM/MIM method because the capacitance of the surge capacitor should be significantly higher than that of the cable.
Impulse current method (ICM)
Explanation
Evaluation
With the impulse current method, a surge voltage pulse is discharged into the cable to activate a breakdown at the fault location. The breakdown produces a travelling wave that moves back and forth between the fault location and the end of the cable. This changes the polarity at these two reflection points, as both are low-resistive seals.
The distance to the fault location can be determined based upon the time it takes for the reflection to repeat. This works particularly well in long cables, since the pulse that propagates through the cable is very wide.
An inductive coupler, which decouples the current on the cable sheath, is used to analyse the travelling pulse. The signals from the coupler can be visualised using a pulse reflectometer. The distance can be calculated based on the time between the individual pulses. To do this, simply mark two consecutive peaks or edges in the travelling wave displayed by the IRG. The distance from the surge voltage generator to the fault location is identical to the difference in metres determined by the device for the two peaks.
The distance to the fault can be determined using the graphical display of the pulse reflectometer. To ensure that all peaks of this travelling wave can be recognised on the screen, the distance range of the IRG must be set so that it represents a multiple of the cable length.
Syscompact 400 portable
Portable cable fault location system for cable fault pre-location and pin-pointing
Decay method
Explanation
Evaluation
Most faults on medium- and even high-voltage cables can be traced using the available surge voltages up to 32 kV. However, this voltage may not be sufficient to trigger a breakdown in the case of intermittent faults (faults that occur only under certain conditions), meaning that the fault location cannot be determined in this way.
In such cases, the decay method can achieve the desired result. In this procedure, the cable is connected to a test voltage source and the capacitance of the cable <em>charged up</em> until the voltage causes a breakdown.
In the decay method, the time domain reflectometer evaluates the voltage wave that oscillates between the fault location and the voltage source after the breakdown
Two sequential positive voltage peaks, signal edges, or zero crossings, for example, are simply marked in the evaluation diagram and the distance is then read off. The difference between these two values, divided by 2 and minus the test leads, gives the distance to the fault location.
As for ICM, a multiple of the cable length should be selected as the default for display so that several oscillations can be shown on the screen.
Syscompact 400 portable
Portable cable fault location system for cable fault pre-location and pin-pointing
ICM differential method
Explanation
The ICM differential method (also referred to simply as the differential method) is one of the pre-location methods that is used in branched voltage networks when a normal reflection measurement is not feasible. High-resistive or intermittent faults can be pre-located using this method. It is called the ICM differential method because two ICM images created in parallel when a surge wave is emitted are compared. To do this, a surge wave generator is connected to both the faulty phase and an intact one at the same time. The ICM measurement is then performed once without a bridge and a second time with a bridge at the cable end from the intact phase to the faulty phase.
If the fault lies on a main core between the generator and the bridge circuit, the measuring device shows the distance between loop and fault location. If, on the other hand, the fault lies in a branch, the measurement gives the distance between the loop and the start of the branch in question.</p></text>
BAUR solutions
Syscompact 400 portable
Portable cable fault location system for cable fault pre-location and pin-pointing
IRG 2000
Time domain reflectometer (TDR)
up to cable length of 65 km
BAUR solutions for
XL cable fault location
Suitable for all cable types:
- HVDC submarine cable links (monopole, bipole)
- HVDC land cable links
- AC submarine cable systems
- Combined AC land and submarine cable systems
Portable devices
Area of application
- For cable fault location at multiple locations of use
- For cable systems with high relevance – high costs in the event of cable failure, high risk for security of supply
FEATURES:
Long cables
All measurement methods
Advantages
- Small and convenient
- Fast transportation to place of use
- Great flexibility of use
- TDR fingerprint in accordance with CIGRE TB 773, CIGRE TB 610, CIGRE TB 680, CIGRE TB 490, CIGRE TB 496
- IEEE 1234-2019
BAUR solution
shirla
Mobile systems
Area of application
- For cable fault location at multiple locations of use
- For cable systems with very high relevance – very high costs in the event of a cable failure, very high risk for security of supply
- Fastest possible availability and operational readiness
FEATURES:
Long cables
All measurement methods
Advantages
- Compact: all cable fault location methods integrated into a single system
- Fast transportation to place of use
- Immediate use
- Great flexibility of use
- Very high degree of efficiency
- Proven system solution
BAUR solution
Systems on wheels for use within the station
Cable test van
Stationary systems
... for long cable systems, can be deployed at both ends
Area of application
- For cable systems with extremely high relevance – extremely high costs in the event of cable failure, extremely high risk for security of supply
- Tailored cable fault location system integrated in a measurement container
- Immediate availability when stored in the cable hall
FEATURES:
Long cables
All measurement methods
Advantages
Saves time
- No loss of time due to transportation
- Immediate deployment in the event of a cable system failure
- Cable fault location within the shortest possible time / on the first day
- Suitable for very long cables
Precision
- Improved positional accuracy thanks to deployment at both ends of the cable
Cost savings
- Reduction of downtime and holding time costs – these can amount to several €100,000 per day
- Investment pays for itself after just one Error
BAUR solution
Fault location systems in containers
Why it pays to invest in XL-CFL.
Interview with Manfred Bawart
Since 2010, BAUR has been developing individual product solutions for fast and efficient fault location on long land and submarine cables. With the powerful systems and extensive expertise of BAUR specialists, critical cable faults on submarine cables have been located rapidly, efficiently, and precisely in recent years. You too can rely on BAUR expertise and the high-performance technologies that have been tried and tested worldwide.
Manfred Bawart
Cable fault location expert and author of specialist publications (published in CIGRE, JICABLE, IEEE PES ICC, IEEE Electrical Insulation Magazine, CIRED, etc.)
What is the technical article about?
The growing use of renewable energies and the transition to e-mobility are increasing the dependency on electrical energy. One source of renewable energy is offshore wind farms, which are connected to the mainland by long cables. However, such high-voltage direct current transmission (HVDC) cables are also used on land. Any faults occurring on these long lines have enormous consequences for a country's electrical infrastructure.
Keeping downtime to a minimum and quickly locating these cable faults requires effective measurement technology. This technology must be versatile, cover various fault location methods, and be capable of adapting to the cable length in order to facilitate reliable fault detection. But which device covers the various measurement methods and can be adapted to the cable length?
The answer to this question and many others can be found in our free article.
Cable fault location on long submarine and land cables with BAUR
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