NMR system for analyzing insulating liquids

Abstract

In an embodiment, a system (100) comprises an electrical device (1) configured to operate by using an insulating liquid (2). The system further comprises an NMR device (3) configured to analyze one or more specific compounds in the insulating liquid.

Description

[0001] This disclosure relates to a system for analyzing insulating liquids and the use of NMR equipment for analyzing insulating liquids.

[0002] US 2017 / 0168034 A1 discloses a device for monitoring the properties of insulating fluids in electrical equipment via microelectronic, optoelectronic, micron and / or nanoscale electromechanical, electrochemical and / or detector components mounted on the surface of a probe, the probe being in contact with the fluid through a valve in an open position. Samples of the fluid can be collected and subjected to laboratory analyses such as gas chromatography and NMR spectroscopy.

[0003] One objective is to provide a system that facilitates rapid and reliable analysis of insulating fluids. Another objective is to provide an efficient method for analyzing insulating fluids.

[0004] First, the system will be described in detail.

[0005] In one embodiment, the system includes an electrical device configured to operate using an insulating liquid. The system further includes an NMR device configured to analyze one or more specific compounds in the insulating liquid.

[0006] Electrical installations such as transformers, reactors, phase shifters, and HVDCs continue to degrade at a certain rate even under normal use, environmental stress, and load conditions. Because these installations are essential equipment in the backbone of any country's electrical system, related technological efforts have been focused on developing condition-based maintenance and condition assessments for these installations. Due to the extremely high availability requirements of these installations (as even a disconnection of one of them could result in a prolonged power outage over a large area), and because the main active components are housed in sealed enclosures and immersed in high-performance insulating fluids, various techniques have been developed over the years to analyze the multiple components dissolved in the insulating fluids of these installations, similar to assessing human health by analyzing compounds found in human blood tests. The most common method for condition assessment of such installations is the periodic laboratory analysis of samples of the insulating fluid.

[0007] However, the inherent challenge of this sampling procedure lies in the long cycle time required to complete each test. The equipment is often located in remote locations and / or protected by stringent access control protocols, making sampling only one step in the overall process. To obtain a valid and representative sample, one or two gallons of insulating fluid are drained from the equipment, necessitating periodic replenishment. All these efforts are aimed at producing a quarter-gallon volume of sample and delivering it to the laboratory.

[0008] Shipping time typically adds several days to the process, as does the time required to complete the analysis in the lab. Overall, it usually takes two weeks from sample collection to receiving the lab report. Once any test results deviate from the expected values, additional tests and samples are needed for a more in-depth investigation, thus triggering the same chain of events again.

[0009] This invention is particularly based on the concept of using NMR technology to identify specific compounds in the insulating fluid of electrical installations. In fact, NMR technology allows for the identification of trace amounts of compounds in insulating fluids. Furthermore, NMR devices are now available in portable versions, enabling analysis directly at the location of the electrical installation, eliminating the need for additional insulating fluid sampling. Therefore, faster and more reliable analysis of the insulating fluid in electrical installations can be achieved.

[0010] Insulating fluids are used for the operation of electrical installations. This means, for example, that an insulating fluid flows through or circulates through a part of the electrical installation during operation, and / or that the enclosure or housing of the electrical installation is filled with an insulating fluid during operation. Insulating fluids can be used for cooling and / or insulation purposes. Insulating fluids are, for example, oil. The heating elements and / or current-transmitting elements of the electrical installation may be surrounded by an insulating fluid during operation.

[0011] The system includes an NMR device. “NMR” stands for Nuclear Magnetic Resonance. This is a well-known technique. An NMR device includes a magnet arrangement for generating a magnetic field in a sample region (also called a “sample volume”), radio frequency (RF) electronics for generating an RF signal, and coils for coupling the RF signal to the sample. Additionally, the NMR device may include electronics for measuring and / or analyzing the sample’s absorption of the RF signal. The magnet arrangement can be a permanent magnet arrangement or an electromagnet arrangement. For example, a permanent magnet arrangement is a Halbach arrangement.

[0012] According to another embodiment, the electrical device is an electrical transformer or self-transformer or reactor or phase shifter or HVDC equipment or similar electrical device using an insulating fluid, the analysis of which is used for condition assessment of the equipment.

[0013] According to another embodiment, the NMR device is a mini NMR device. Specifically, the NMR device is small enough to be installed in or at the location of an electrical installation. For example, the NMR device has a size of less than 50 cm. That is, the maximum extension of the NMR device in any spatial direction is, for example, less than 50 cm. In particular, the NMR device can be portable.

[0014] NMR equipment can be configured for field analysis. This means that, on the one hand, the NMR equipment is small enough to be installed directly at or near the electrical installation. NMR equipment can comprise a single compact unit or several independent compact sub-units. The NMR unit or each sub-unit can be small enough to be installed inside the enclosure of the electrical installation.

[0015] In the system, the NMR device can be installed outside the transformer enclosure. As an example, the NMR device can be installed at the enclosure or separately from it. The NMR device can also be installed inside the enclosure.

[0016] Miniature NMR devices or portable NMR devices include, for example, a permanent magnet arrangement and electronic circuitry with a silicon chip. The silicon chip may include radio frequency electronics for generating radio frequency signals. The silicon chip may also include electronics for measuring and analyzing the absorption frequencies of different compounds.

[0017] Miniature NMR devices or portable NMR devices are described, for example, in the paper by Dongwan Ha et al., “Scalable NMR spectroscopy with semiconductor chips,” *Proceedings of the National Academy of Sciences (PNAS)*, 2014, Vol. 111, No. 33, pp. 11955-11960; or in the paper by Ka-MengLei et al., “Portable NMR with Parallelism,” *Analytical Chemistry*, 2020, 92, 2112-2120. The contents of these two papers are incorporated herein by reference.

[0018] An NMR device designed for field operation alongside electrical installations includes sufficient electrical and magnetic shielding for operation at or near electrical installations, such as power transformers. Furthermore, adequate mechanical robustness is required for structural reasons and to avoid the NMR measuring equipment being affected by mechanical vibrations generated by the transformer.

[0019] By using NMR equipment for on-site operation, the cycle time required for sample analysis can be shortened. There is no need to transport samples to a laboratory. Furthermore, samples can be automatically obtained from insulating liquids in either continuous or intermittent manner.

[0020] According to another embodiment, the NMR device is located outside the electrical device and is fluidly connected to or can be fluidly connected to the electrical device. "External" means that the NMR device is not integrated into the electrical device. Instead, it is a stand-alone device. For example, during operation, the NMR device is located outside the housing or enclosure of the electrical device. Alternatively, during operation, it can be placed inside the electrical device, for example, within the housing of the electrical device.

[0021] "Fluid connection" means that a fluid connection exists that allows a portion of the insulating liquid from the electrical installation to flow into the sample area of ​​the NMR device.

[0022] According to another embodiment, the system is configured to supply a sample of insulating liquid from an electrical device to the NMR device in a continuous or intermittent manner. For example, when connected to an electrical device, a continuous flow of insulating liquid flows through the sample region of the NMR device. Alternatively, a sample of insulating liquid can be stored in the sample region of the NMR device for a period of time (e.g., at least 1 minute) without flow, and after this time, it can be replaced by another sample of insulating liquid.

[0023] According to another embodiment, the NMR device is reversibly fluidly coupled to an electrical device. Specifically, the fluid connection between the NMR device and the electrical device can be repeatedly established and disengaged. This allows the NMR device to be sequentially fluidly coupled to two or more electrical devices and to analyze the insulating fluid of each electrical device.

[0024] According to another embodiment, the NMR device can be fluidly connected to, or simultaneously fluidly connected to, multiple electrical devices. Specifically, when multiple NMR devices are connected simultaneously, a fluid connection is established from the NMR device to each electrical device. In this way, a sample of insulating fluid from each electrical device can flow into the sample area of ​​the NMR device.

[0025] According to another embodiment, the NMR device is configured to analyze the insulating fluid of multiple electrical devices simultaneously or sequentially. For example, the NMR device includes a separate sample region for each electrical device simultaneously fluidly connected thereto, or samples from two or more electrical devices are mixed in a sample region of the NMR device. Alternatively, when several electrical devices are simultaneously fluidly connected, samples from different electrical devices are sequentially delivered to the sample region for analysis in turn.

[0026] According to another embodiment, the NMR device is configured to analyze one or more of the following compounds in an insulating liquid: dissolved gases, free gases, combustible gases, non-combustible gases, solid and / or liquid insulation aging markers, contaminants, water, dissolved gases, soluble acids, aldehydes, alcohols, oxidation byproducts, peroxides, oxidation inhibitors and additives, oil, and particulate matter.

[0027] According to another embodiment, the system is configured to determine operating parameters of an insulating liquid based on compounds analyzed by means of an NMR device. For example, the system is configured to analyze and interpret the absorption spectrum of a sample, determine the concentration and type of compounds in the sample, and thereby determine one or more operating parameters of an electrical device.

[0028] According to another embodiment, the operating parameters are one or more of the following: neutralization index, dielectric loss factor, power factor, moisture content, color, interfacial tension, oxidation stability, breakdown voltage, and dissolved gas analysis (combustible and non-combustible gases).

[0029] According to another embodiment, the system further includes a user interface. The user interface is configured to inform the user of the results of analysis of the insulating liquid using an NMR device. For example, the user interface includes a display. The system can be configured to display the identified compounds (multiple compounds), optionally also their concentrations and / or (multiple) operating parameters on the display.

[0030] According to another embodiment, the system is configured to generate an alarm based on the results of analysis of the insulating fluid using an NMR device. Optionally, the system can be configured to generate expert action recommendations along with the alarm. For example, an alarm is generated if one or more specific compounds are determined to be present in the insulating fluid, or if the concentration of one or more specific compounds in the insulating fluid exceeds a predetermined threshold. The alarm can be a visual and / or audible indicator. The alarm can instruct the operator that maintenance must be performed.

[0031] Next, the intended use of the NMR device is explained in detail. All the features disclosed in the system are also disclosed regarding its intended use, and vice versa.

[0032] In this embodiment, the NMR device is used to analyze the insulating fluid of the electrical installation. Specifically, the NMR device is used to analyze the insulating fluid to determine the presence of one or more specific compounds.

[0033] According to an embodiment, the analysis of the insulating fluid is performed on-site at the electrical installation. For example, the analysis is performed immediately after a sample of the insulating fluid is extracted from the electrical installation. During the analysis of the insulating fluid, the NMR equipment can maintain fluid contact with the electrical installation.

[0034] According to an embodiment, the insulating fluid is analyzed during operation of the electrical device. During operation of the electrical device, the insulating fluid flows through or circulates through the electrical device and / or the electrical device is at least partially filled with the insulating fluid.

[0035] The system for analyzing insulating fluids will be explained in more detail below with reference to the accompanying drawings, which are based on exemplary embodiments. The drawings are included to provide further understanding. In the drawings, elements that are structurally and / or functionally identical may be indicated by the same reference numerals. It should be understood that the embodiments shown in the drawings are illustrative and not necessarily drawn to scale. Descriptions of elements or components will not be repeated for subsequent drawings as long as their functions correspond to each other in different drawings. For clarity, elements may not appear with corresponding reference numerals in all figures.

[0036] Figure 1 , Figure 3 and Figure 4 Different exemplary embodiments of the system are shown. Figure 2 An exemplary embodiment of an NMR device is shown.

[0037] According to Figure 1 In a first exemplary embodiment of a system for analyzing insulating fluids, system 100 includes an electrical device 1, an NMR device 3, a processor 5, and a user interface 4, i.e., a display 4. The electrical device 1 is implemented herein as a transformer, particularly a high-voltage transformer or a power transformer. During operation of the transformer 1, the tank or casing of the transformer 1 is filled with an insulating fluid 2, which may be oil. This insulating fluid 2 undergoes degradation.

[0038] To detect this degradation, the NMR device 3 is fluidly connected to the transformer 1. This connection is achieved via a fluid connection 6 (e.g., a pipe) extending from the transformer 1 to the NMR device 3 and returning from the NMR device to the transformer 1. In this way, a sample of the insulating liquid 2 can be supplied to the NMR device 3 (i.e., its sample area) in a continuous or intermittent manner.

[0039] The NMR apparatus 3 is configured to analyze one or more specific compounds in the insulating liquid 2. These specific compounds may be, for example, dissolved gases, free gases, combustible gases, non-combustible gases, solid and / or liquid insulation aging markers, contaminants, water, soluble acids, aldehydes, alcohols, oxidation byproducts, peroxides, oxidation inhibitors and additives, oil, or particulate matter. Specifically, the NMR apparatus may be configured to detect the presence of such a compound in the insulating liquid 2 and / or the concentration of such a compound in the insulating liquid.

[0040] The NMR device 3 is connected to the processor 5. The processor 5 is configured to determine the operating parameters of the insulating liquid 2 based on the compounds analyzed by means of the NMR device 3. For example, based on information provided by the NMR device 3, such as measured absorption spectra, the processor 5 can determine the neutralization index, dielectric loss factor, power factor, moisture content, color, interfacial tension, oxidation stability, breakdown voltage, and / or dissolved gas analysis. The processor 5 is connected to the display 4, allowing the operating parameters to be displayed on the display 4.

[0041] Figure 2 A detailed view of an exemplary embodiment of an NMR device 3 that can be used in system 100 is shown. The NMR device 3 is either a mini NMR device or a portable NMR device. It includes a magnet arrangement 35, such as a Hellbeck permanent magnet arrangement. This magnet arrangement 35 surrounds a sample region 34, into which a sample of insulating liquid 2 is guided via a fluid connection 6. A transmitter coil and a receiver coil surround the sample region 34 and are connected to a silicon chip 30, which is an IC chip. The silicon chip 30 includes a transmitter 31 and a receiver 32, as well as electronics 33 for generating radio frequency signals and for analyzing signals received by means of the receiver 32. This analysis is performed in… Figure 2 The figure shows a peak in the absorption spectrum of the radio frequency signal, indicating the presence of a specific compound in the sample of insulating liquid 2. The overall size of the NMR device 30 is, for example, no more than 50 cm in each spatial direction.

[0042] The NMR device 3 is configured to be robust and electrically shielded for installation at the site of the electrical installation 1. As an example, the NMR device 3 can be installed directly at the electrical installation 1, for example, on a tank wall. The NMR device 3 can be installed on the outside of the tank wall. In some embodiments, the NMR device 3 can also be installed inside the tank. Furthermore, the NMR device 3 is configured to analyze circulating liquids.

[0043] exist Figure 3 In an exemplary embodiment, system 100 is shown to include three electrical devices 1, each implemented as a transformer. An NMR device 3 is reversibly fluidly connected to each transformer 1. In this way, one NMR device 3 can be sequentially connected to several transformers 1 and can be used to analyze the insulating fluid 2 of each transformer 1.

[0044] exist Figure 4 In an exemplary embodiment, system 100 includes a plurality of electrical devices 1, each of which is implemented as a transformer 1. However, with Figure 4 In contrast, the NMR device 3 is simultaneously fluidly connected to each transformer 1 via the fluid connection 6. Therefore, the NMR device 3 can be used to analyze the insulating liquid 2 of the transformer 1 simultaneously or sequentially.

[0045] As mentioned above, Figures 1 to 4 The embodiments shown represent exemplary embodiments of the system and NMR device. Therefore, these exemplary embodiments do not constitute a complete list of all embodiments of the system and NMR device. Actual systems and NMR devices may differ from the embodiments shown, for example, in terms of arrangement, apparatus, and components.

[0046] List of reference numerals in the attached diagram: 1. Electrical installations 2. Insulating liquid 3. NMR equipment 4. User Interface 5. Processor 6. Fluid connection 30. Silicon chip 31. Transmitter 32. Receiver 33. Electronic devices 34. Sample area / sample volume 35. Magnet Arrangement 100. Systems for analyzing insulating fluids

Claims

1. A system (100) comprising: - Electrical device (1), which is configured to operate by using an insulating liquid (2), - NMR device (3), which is configured to analyze one or more specific compounds in the insulating liquid (2).

2. The system (100) according to claim 1. in, The NMR device (3) is fluidly connected to the electrical device (1) such that a portion of the insulating liquid (2) can flow to the sample region (34) of the NMR device (3).

3. The system (100) according to any one of the preceding claims, wherein, - The electrical device (1) is an electrical transformer or self-transformer or reactor or phase shifter or HVDC equipment.

4. The system (100) according to any one of the preceding claims, wherein, - The NMR device (3) is a mini NMR device (3) with a size of less than 50 cm.

5. The system (100) according to any one of the preceding claims, wherein, - The NMR device (3) is located outside the electrical device (1).

6. The system (100) according to any one of the preceding claims, wherein, The NMR device (3) is installed at the electrical device.

7. The system (100) according to any one of the preceding claims, wherein, The NMR device (3) is installed in the electrical device.

8. The system (100) according to any one of the preceding claims, wherein, - The system (100) is configured to supply the NMR device (3) with a sample of insulating liquid (2) from the electrical device (1) in a continuous or intermittent manner.

9. The system (100) according to any one of the preceding claims, wherein, - The NMR device (3) is reversibly fluidly connected to the electrical device (1) so that the NMR device (3) can be fluidly connected to two or more electrical devices (1) in sequence and analyze the insulating liquid (2) of the electrical device (1).

10. The system (100) according to any one of the preceding claims, wherein, - The NMR device (3) is simultaneously fluidly connected or can be fluidly connected to multiple electrical devices (1). - The NMR device (3) is configured to analyze the insulating liquid (2) of the plurality of electrical devices (1) simultaneously or sequentially.

11. The system (100) according to any one of the preceding claims, wherein, - The NMR device (3) is configured to analyze one or more of the following compounds in the insulating liquid (2): dissolved gas, free gas, combustible gas, non-combustible gas, solid and / or liquid insulation aging markers, contaminants, water, soluble acid, aldehyde, alcohol, oxidation byproducts, peroxide, oxidation inhibitors and additives, oil, and particulate matter.

12. The system (100) according to any one of the preceding claims, wherein, - The system (100) is configured to determine the operating parameters of the insulating liquid (2) based on the compounds analyzed by means of the NMR device (3).

13. The system (100) according to claim 9, wherein, - The operating parameters are one or more of the following: neutralization index, dielectric loss factor, power factor, moisture content, color, interfacial tension, oxidation stability, breakdown voltage, and dissolved gas analysis.

14. The system (100) according to any one of the preceding claims further comprises: - User interface (4), which is configured to notify the user of the system (100) of the results of the analysis of the insulating liquid (2) with the NMR device (3).

15. The system (100) according to any one of the preceding claims, wherein, - The system (100) is configured to generate an alarm with expert action recommendations based on the results of analysis of the insulating liquid (2) using the NMR device (3).

16. The use of NMR equipment (3) for analyzing the insulating liquid (2) of electrical installations (3), wherein, - The analysis of the insulating liquid (2) was carried out on-site at the electrical installation (1).

17. The use of the NMR device (3) according to claim 16, wherein, - The insulating liquid (2) is analyzed during the operation of the electrical device (1).

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