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EP-4739989-A1 - METHOD AND DEVICE FOR DETECTING A LEAK IN A SUPPLY NETWORK

EP4739989A1EP 4739989 A1EP4739989 A1EP 4739989A1EP-4739989-A1

Abstract

The invention relates to a method for detecting a leak, and to a device suitable therefor, in a supply network that comprises a pipeline system through which a fluid is conveyed, wherein a pressure (p(t)) of the fluid and a volumetric flow (V(t)) of the fluid are detected as a function of time by measuring at various locations (x1, x2, ...xN) of the pipeline system. The invention is characterised in that, at a first location (x1), for a first defined duration (T1), the pressure in the pipeline system is modulated using a first predefinable reference signal (M1), and curves of the modulated pressure signal and volumetric flow signal are preferably recorded at this first location (x1) and, if a time difference (Δt1) is detected between defined signal portions of the pressure signal and the volumetric flow signal, a first distance of a leak from this first location (x1) is determined from this time difference (Δt1). The method according to the invention and appropriately designed devices are in particular applicable for detecting supply network leaks.

Inventors

  • KLEHR, STEFAN
  • LABISCH, DANIEL
  • VON DOSKY, STEFAN

Assignees

  • Siemens Aktiengesellschaft

Dates

Publication Date
20260513
Application Date
20240822

Claims (16)

  1. 1. Method for detecting a leak in a supply network with a piping system through which a fluid is conducted, wherein at N different locations (xl, x2, ...xN) of the piping system, a pressure (p(t) ) of the fluid and a volume flow (V (t) ) of the fluid in the pipeline system are measured, characterized in that at a first location (xl) for a first defined period of time (TI) the pressure in the pipeline system is modulated with a first predeterminable reference signal (Ml), and preferably at this first location (xl) curves of the modulated pressure and volume flow signal are recorded and upon detection of a time difference (Atl) between defined signal components of the pressure signal and the volume flow signal, a first distance (El) of a leak to this first location (xl) is determined from this time difference (Atl).
  2. 2. Method according to claim 1, characterized in that at a second location (x2) for a second defined period of time (T2), which can be equal to the first period of time (TI), the pressure in the pipeline system is modulated with a second predeterminable reference signal (M2), which can be equal to the first reference signal (M1), and preferably at this second location (x2) profiles of the modulated pressure and volume flow signal are recorded and upon detection of a time difference (At2) between defined signal components of the pressure signal and the volume flow signal, a second distance (E2) of a leak to this second location (x2) is determined from this time difference (At2) and the method is repeated at further locations (x3, x4, ...) and the position of the leak in the pipeline system is determined from a plurality of the distances (E3, E4, ...) determined in this way.
  3. 3. Method according to claim 1 or 2, characterized in that the determination of the distances of the leakage to the locations (xl, x2, ...xN) takes place at different measuring times (tl, t2, ...tM).
  4. 4. Method according to claim 2 or 3, characterized in that at least partially the locations at which the pressure in the pipeline system is modulated are different from the locations at which the pressure and the volume flow of the fluid are measured.
  5. 5. Method according to one of claims 1 to 4, characterized in that the measurement devices for detecting the pressure and the volume flow of the fluid are positioned at different locations in the same pipeline section.
  6. 6. Method according to one of the preceding claims, characterized in that the time periods (Ti) during which the pressure in the pipeline system is modulated and the time periods during which the pressure and the volume flow of the fluid are measured coincide at least partially.
  7. 7. Method according to one of the preceding claims, characterized in that the modulation of the pressure can be a periodic signal with a predeterminable amplitude, frequency and phase and accordingly the time differences between the pressure and volume flow signal determined at a location are phase differences.
  8. 8. Method according to claim 7, characterized in that in the case of a periodic modulation signal, the phase between the pressure signal and the volume flow signal is influenced by varying the frequency of the pressure signal.
  9. 9. Method according to one of the preceding claims, characterized in that the measured pressure signal with is correlated with the measured volume flow signal.
  10. 10. Method according to one of the preceding claims, characterized in that in order to improve the signal-to-noise ratio, the time periods during which the pressure and the volume flow of the fluid are measured are selected to be as long as possible.
  11. 11 . Method according to one of the preceding claims, characterized in that the amplitude and frequency of the modulation signal are selected as a function of properties of the pipeline system.
  12. 12. Method according to one of the preceding claims, characterized in that the metrological detection of the pressure and the volume flow of the fluid and/or the pressure modulation are controlled.
  13. 13. Method according to one of claims 1 to 12, characterized in that the supply network is a water distribution network and the locations are feed points for water into the pipeline system.
  14. 14. Method according to one of claims 1 to 12, characterized in that the supply network is a hydrogen distribution network and the locations are feed points for hydrogen into the pipeline system.
  15. 15. Device (1) for detecting a leak in a supply network with a pipeline system through which a fluid is conducted, comprising - a modulation device (2) which is designed to modulate the pressure of the fluid with a predeterminable reference signal, - a computer-aided control unit (3) for controlling the modulation device (2), - a detection system (4) which can be coupled to the piping system at a location (xl) and has a pressure sensor (4A) for measuring the pressure of the fluid and a flow sensor (4B) for measuring the volume flow of the fluid, - a processing unit (5) which is communicatively connected at least to the control unit (3) of the device for modulation (2) and the detection system (4) and is designed to determine a distance (El) to a leak, characterized in that the courses of the modulated pressure and volume flow signal recorded by means of the detection system (4) are compared and, upon detection of a time difference (Atl) between defined signal components of the pressure signal and the volume flow signal, a distance of a leak to this location (xl) is derived from this time difference (Atl).
  16. 16. Computer-aided processing unit (6) which is connected to at least one device (1) according to claim 15 and is designed to carry out the method according to one of claims 1 to 14.

Description

Description Method and device for detecting a leak in a supply network The invention relates to a method for detecting a leak in a supply network having a piping system through which a fluid is conducted, wherein a pressure of the fluid and a volume flow of the fluid are measured at various locations in the piping system as a function of time. The invention further relates to devices suitable for the method. Drinking water loss due to dilapidated piping systems is a major problem in many countries around the world. Enormous quantities of drinking water are lost through undetected leaks. There is a global need for action in this area, as climate change, the growing world population, and increasing industrialization are making water an increasingly scarce and expensive resource. A variety of methods for detecting leaks in water distribution networks are known from the state of the art. Leak detection techniques can generally be divided into two categories: external and internal methods. External methods detect leaks by looking for signs of leaks outside the piping system. One example is visual inspection. Another method is listening to the flow noise at various points along the pipe, from which the location of the leak can be determined. Internal methods, such as internal inspection, attempt to find leaks using sensors that measure state variables within the pipes. This category includes a variety of mathematical, computational, and signal processing methods. From Silva et al. , JAFR 1996 "Pressure wave behavior and leak detection in pipelines", Comp. And Chemical Eng . process dings 6th Eur . Symp . (Rhodes) 20, pp. 491-6, an online computing technique is known in which the data of the transients caused by a leak are recorded by a computer, which displays the pressure transient curve and enables the leak location to be identified. This method is based on the fact that the pressure wave generated by a leak is accompanied by a sudden drop in pressure. GB2444955A discloses a leak detection device for underground water distribution pipes in which a pressure wave is transmitted from a hydrant to the underground pipe. A pressure sensor detects pressure fluctuations in the fluid in the pipe caused by the pressure wave, which are reflected by discontinuities (e.g. leaks) in the system. A control unit records the measured pressures, analyses them and calculates the distance between the pressure sensor and a detected discontinuity. A disadvantage of the leak detection approach described in GB2444955A is that a significant pressure surge is required to generate reflections at the leak point, which puts a strain on the piping system. Furthermore, it is a temporary measurement setup that requires personnel and cannot be permanently integrated into existing infrastructure. The measurement setup only works for large leaks, and other faults (e.g., branches or changes in cross-section) lead to misinterpretations. Furthermore, the detection range is very limited. WO2019/160433A1 discloses a method for processing transient events in a distribution network with a specific network topology based on wavefront characteristics recorded at high speeds by a plurality of sensors at specific measuring locations in the distribution network. In the method, an arrival time of a wavefront caused by a specific transient event is recorded at least at a subset of the measuring locations by a respective sensor of the N sensors. A location of the specific transient event in the distribution network is then determined depending on differences in the determined arrival times of the wavefront that was detected by the sensors at the subset of the measuring locations. An event type of the transient event in the distribution network is then classified using the specific location of the transient event in the distribution network, using the detected arrival times of the wavefronts, and using the specific network topology of the distribution network. The approach described in W02019/160433A1 also has the disadvantage that very strong pressure gradients (e.g. caused by a pipe burst) place a strain on the piping system. Furthermore, many closely distributed measuring points are necessary, which often leads to difficulties, particularly with regard to the power supply of the measuring points. All measuring points require a very precise time and must be precisely synchronized. In particular, both of the aforementioned methods are unsuitable for continuous monitoring of existing leaks integrated into the piping system of a water supply network. It is therefore an object of the present invention to overcome the disadvantages of the prior art and to provide an improved method and device for detecting leaks, in particular existing leaks, in a supply network, in particular a water supply network. This object is achieved by a method having the features of claim 1. Furthermore, the object is achieved by a device according to claim 15 and a computer-aided proces