MONITORING PROCEDURES OF AN ELECTRIC ENERGY TRANSFER FACILITY

Description

[0001] The invention relates to a monitoring method for an electrical power transmission device with a first phase conductor and a second phase conductor, wherein at the same time a temperature of the first phase conductor and a temperature of the second phase conductor are determined, the determined temperature of the first phase conductor is compared with the determined temperature of the second phase conductor, and a signal is sent if there is a deviation between the determined temperatures.

[0002] An electrical power transmission device with a first phase conductor and a second phase conductor is known, for example, from German patent application DE 10 2016 213 158. This application describes a switching device arrangement which has several interrupter units within an encapsulated housing, each of which is part of a phase conductor. The figure shows a first phase conductor and a second phase conductor with a first interrupter unit and a second interrupter unit, respectively. US patent US 4,794,327 discloses a sensor module which is powered by a high-voltage line. Several of these sensor modules can be arranged on several phase conductors, measuring various quantities such as electric current, electric voltage, or conductor temperature.To wirelessly connect the sensor modules to a common evaluation unit, a clocked transmission of measured values ​​from the respective sensor modules is proposed. US Publication US 2011 / 0137483 A1 describes the remote monitoring of an overhead power line conductor, taking the conductor temperature into account. Chinese Utility Model CN ​​203225200U describes a vacuum circuit breaker equipped with a temperature sensor. US Publication US 2014 / 0180616 A1 describes a system and a method for calculating the transmission capacity of a transmission line. International Publication WO 2017 / 174994 A1 describes a method for detecting contact faults at contact points. Elevated temperatures can occur at faulty contact points. Temperatures at the contact points are monitored to identify contact faults.

[0003] Switchgear assemblies are subject to high demands regarding the power they can transmit. At the same time, the dimensions of such electrical power transmission equipment must be compact. Therefore, electrical power transmission equipment is often designed with only minimal reserves. To ensure reliable operation under these conditions, even in the event of overloads or faults, dependable monitoring of the electrical power transmission equipment is essential.

[0004] The task is therefore to specify a suitable monitoring procedure for an electrical power transmission device that enables the safe operation of a first and a second phase conductor.

[0005] According to the invention, the problem in a monitoring method of the type mentioned at the outset is solved by verifying the deviation by measuring the rate of change of a determined temperature of a phase conductor and / or the deviation of the determined temperatures.

[0006] Electrical power transmission equipment serves to transport electrical energy between two points. This requires the transmission of a corresponding amount of power between these points. Driven by a potential difference, electrical currents are conducted via phase conductors. Phase conductors are electrically conductive components that serve to carry a current. Phase conductors are used, for example, as busbars, valve bodies, coupling devices, in cables, on switching devices, in outdoor installations (AIS), gas-insulated switchgear (GIS), in transformers, instrument transformers, etc. The phase conductors must be electrically insulated. For this purpose, fluid insulation, preferably in gaseous form, can be used. However, electrically insulating fluids in a liquid state can also be used.The fluid can, for example, be contained within an encapsulation housing and pressurized there. In this case, the encapsulation housing serves as a pressure vessel to withstand a differential pressure between the interior of the encapsulation housing and its surroundings. A phase conductor, which is at least partially located within the encapsulation housing, is electrically insulated within the housing by the electrically insulating fluid flowing around it.

[0007] Depending on the voltage system used, e.g., direct current (DC) or alternating current (AC), at least one first phase conductor and one second phase conductor must be used. For example, in a DC system, the first phase conductor can carry the forward current and the second phase conductor the return current. In an AC system, especially a multi-phase AC system, more than two phase conductors, preferably three, can be used to transmit electrical power. Each phase conductor is subjected to an alternating voltage (AC), which drives an alternating current in the phase conductor. In both AC and DC applications, the preferred load on the phase conductors is chosen such that each phase conductor carries approximately the same current, i.e., the same amount of energy. Due to the current load on the phase conductor, heating occurs in the phase conductor.The electrical insulation used must be resistant to these heating processes. With a preferably uniform load on the phase conductors belonging to an electrical power transmission system, the individual phase conductors typically experience a similar heat load. However, due to disturbances or asymmetrical loads, particularly in AC systems, different current loads and consequently different heat loads can occur. Especially in the case of disturbances, localized or point-like impedance increases can lead to correspondingly increased thermal loads on the affected phase conductor. For example, fault-related hot spots can occur in individual phases at electrical switching devices (interrupter units) due to contact problems such as contact corrosion, wear, faulty switching movements, etc.By measuring the temperatures on each of the phase conductors—at least on the first and second phase conductors—it's easy to determine whether the individual phase conductors are evenly loaded relative to each other. External influences, such as solar radiation or other heat or cold phenomena, generally affect the phase conductors uniformly. Evaluating temperature differences allows for the compensation of such external influences. For example, temperature sensors can be placed at critical points, evenly distributed, or within a specific section of a phase conductor. Energy-harvesting sensors can be used for this purpose; these sensors derive the necessary energy from the quantity being measured, such as temperature, to perform their measurement function.For example, it is possible to generate electrical energy based on thermal differences between the surface of the phase conductor and its surroundings, and to use this energy to measure the phase conductor's temperature. Furthermore, this electrical energy can be used to transmit the information about the measured values. Such transmission can, for example, be wireless.

[0008] Once the temperatures of the phase conductors have been determined, they are independent of the electrical state of the phase conductor. For example, even when the phase conductors are switched off (no current flow), their temperatures can be monitored and evaluated. Ideally, this evaluation should be performed by comparing the temperatures of the first and second phase conductors. In an idealized environment, with a uniform load on the phase conductors (e.g., both phase conductors have no current flow or both have the same current load), the temperature on both phase conductors will be approximately the same at the same time. Even with external thermal events, such as heat radiation, the temperature of the phase conductors will be approximately the same.In solar energy systems, heating or cooling elements, uneven influence of disturbance variables can lead to temperature variations on the phase conductors. These temperature variations are one of the criteria for evaluation. If a deviation occurs in the temperatures measured on two or more phase conductors, this suggests an atypical situation on one of the phase conductors. For example, a loose connection can lead to a hot spot. Furthermore, worn switch contacts can cause local temperature increases. If this occurs on only one phase conductor, it cannot be assumed to be due to normal aging or a general change in the phase conductors of the same nature, but rather indicates an event that requires further investigation.This makes it possible to trigger a signal if a temperature discrepancy occurs between the temperatures measured on the two phase conductors. This signal can be triggered in various ways. It can take the form of a warning or an immediate action on the switchgear, such as an emergency shutdown. Before a signal is triggered, an additional indicator can be used to verify the signal based on the temperature difference, which can also be zero. Alternatively, verification can be configured to occur only after a signal has been triggered. Further steps can then be taken following a signal.

[0009] In addition to measuring the temperatures on the first and second phase conductors at the same time, temperature changes on one phase conductor are also monitored over time intervals. These temperature changes can occur at different rates. For example, a temperature change might correspond to an increase or decrease in the (current) load on the phase conductors. Such an increase in a specific time constant is therefore attributable to normal operating behavior. However, if a temperature deviation occurs on a selection of phase conductors (single or multiple from a group of phase conductors) and no correlation with changes in electrical load (changed current flow) is apparent, this indicates an irregularity that requires further investigation.In particular, a rapid increase in temperature or temperature deviations indicates a fault. The transmission of electrical energy is typically associated with long time constants with respect to thermal changes. A high rate of change leads to a steep increase in the measured temperature or temperature deviation. A high rate of change, for example, on only one of the phase conductors, also leads to a high rate of change in the measured temperature difference. Accordingly, if temperature deviations are present on the phase conductors, verification can be performed by measuring the rate of change of a temperature or temperature deviation before any signal is generated.

[0010] A further embodiment may provide that at the same time a first electric current loading the first phase conductor and a second electric current loading the second phase conductor are determined, the determined electric currents are compared, and if there is a deviation between the determined currents, a verification of the deviation of the determined temperatures is carried out.

[0011] In electrical power transmission systems, the electric current flowing on a phase conductor and the voltage driving that current are typically measured. This information is used, for example, to control protective devices. Generally, a change in electric current should correspond to a corresponding change in the temperature of the phase conductor carrying it. It's important to note that, due to time constants, a change in temperature follows an increase or decrease in electric current with a time lag. Therefore, a potential delay must be considered to avoid misinterpretations. Generally, however, an increased load on a phase conductor should result in an increased temperature on that conductor. Conversely, a decrease in the load on the phase conductor is generally accompanied by a decrease in its temperature.Therefore, it is advantageous to compare the current of the first phase conductor with the current of the second phase conductor and determine any deviation. A deviation in current should correspond to a deviation in the temperatures of the phase conductors, so that a temperature deviation can be verified by a deviation in current. It may also be possible, for example, to relate the measured temperatures to the measured currents and, if they correspond, to conclude that there is an asymmetrical load between the phase conductors. This could be attributed to a specific operating regime and not necessarily to a fault in one of the phase conductors.

[0012] It may be advantageous to provide that a temperature deviation and a current deviation of the respective phase conductors are checked with regard to the similarity of the temperature deviation and the current deviation.

[0013] In addition to temperature variations between different phase conductors (the variation can also be zero), there can also be variations in the current load on the different phase conductors (the current variation can also be zero). Similar temperature and current variations indicate a corresponding asymmetric load. However, if the current load is the same (no current variation, but a temperature variation), this suggests an irregularity in the electrical current load, which can point to a fault on one phase conductor. Accordingly, this testing and cross-testing of temperature and current variations on the respective phase conductors and between the phase conductors can serve as verification, particularly as a signal before delivery.However, it can also be stipulated that verification only takes place after a signal has been issued. Depending on the requirements, the various verification parameters, e.g., the rate of change of temperature, comparison of the change in electrical currents and temperatures on the respective phase conductor, temperature and current deviations between the phase conductors, etc., can lead to an increased quality of monitoring the load on the electrical power transmission equipment.

[0014] Advantageously, it can also be provided that a check is carried out to determine whether a deviation has left a specified tolerance band.

[0015] A tolerance band can be defined for deviations in both temperature and electrical current. Depending on the electrical power transmission network or equipment, asymmetrical loads can occur, for example, due to asymmetrical consumers. In such cases, it is advantageous to define a tolerance band within which temperature and current differences between phase conductors are acceptable. Only when these tolerance bands are exceeded can this indicate a fault, necessitating a signal. In addition to a tolerance band for the deviations themselves, a time-based tolerance bank can also be defined for successive measurements of different physical quantities, such as electrical current and temperature.This takes into account the always present time constant, with which a temperature increase or decrease is delayed in relation to a change in current.

[0016] A further advantageous embodiment may provide that, based on determined measured values, in particular for temperatures and / or currents, a forecast for the course of the temperature load of at least one of the phase conductors is made.

[0017] Based on measured temperatures and, if applicable, electrical current, a temperature profile can be predicted. The time constant of the phase conductor can also be incorporated into this prediction. For example, depending on the phase conductor's application—e.g., fluid insulation, solid insulation, enclosure, etc.—different heat dissipation behaviors can occur. Depending on these factors, the phase conductor exhibits a different time constant with which a thermal change occurs. Considering this time constant, for instance, the reaching of a threshold value can be predicted in the case of a temperature increase and a subsequent, time-delayed further increase. A prediction function describes the expected time course of a temperature change. For example, it is possible to include the slope (1.The derivative of the forecast function allows us to predict the time at which a threshold value will be reached based on the change in temperature. A gradient method can be used to determine minima and maxima. Particularly in cases caused by disturbances, a switchover can be implemented in a timely manner to prevent a predicted threshold value from being reached.

[0018] Another advantageous design may provide that the process steps are carried out in a decentralized data processing system.

[0019] The monitoring procedure is preferably carried out continuously. Depending on the available sensors or computing capacity, appropriate measurements, comparisons, and necessary conclusions or forecasts can be generated at shorter or longer intervals. With a decentralized data processing system, a large amount of information can be collected and linked, for example, along a phase conductor. This allows for the diagnosis of local deviations in measured values ​​along a phase conductor, even over a long distance. Decentralized data processing enables the decentralized collection, processing, and analysis of data. This provides a cost-effective way to make sufficient computing capacity available to monitor even widely spaced phase conductors, such as those found in transmission networks.Such phase conductors can span distances of several hundred kilometers, during which temperature measurements can be taken at numerous points along their length. This allows for the determination of both the temperature difference between phase conductors and the temperature difference along the entire length of the phase conductor.

[0020] Another advantageous embodiment may provide that a computer program product, which, when the program is executed on a data processing system, is configured to perform a procedure according to one of the preceding steps.

[0021] Continuous monitoring offers the particular advantage of enabling repeated temperature measurements at short intervals. This allows for rapid responses to temperature changes. Furthermore, it enables the provision of accurate forecasts for expected temperature trends. The data processing system can be decentralized.

[0022] A further object of the invention is to provide an electrical energy transmission device with a first phase conductor and a second phase conductor as well as a first current measuring device for the first phase conductor and a second current measuring device for the second phase conductor, wherein the first phase conductor has a first temperature sensor and the second phase conductor has a second temperature sensor, which can be monitored by a monitoring method.

[0023] According to the invention, the problem in an electrical energy transmission device of the type mentioned above is solved by connecting at least the temperature sensors to a decentralized computer system which is configured to carry out the method according to one of claims 1 to 6.

[0024] An electrical power transmission device is used to transmit electrical energy. Phase conductors are employed for this purpose, which, driven by potential difference, carry an electric current. The phase conductors are electrically insulated. To monitor the current load on the phase conductors, a first current measuring device and a second current measuring device are arranged on both the first and second phase conductors, allowing the current load for each to be determined. Additionally, a first temperature sensor can be assigned to the first phase conductor and a second temperature sensor to the second phase conductor. This makes it possible to determine not only the current load of each phase conductor but also its thermal load.This allows, for example, the determination of both current and temperature loads, the examination of any deviations in the current and heat loads of individual phase conductors, and the dismissal of any thermal deviations that may occur as being due to the operating conditions. Only when faults occur, such as those exceeding a tolerance band, can a corresponding signal be triggered.

[0025] It is planned that at least the temperature sensors will be connected to a decentralized computer system.

[0026] Integrating temperature sensors into a decentralized computer system allows for decentralized processing of the sensor data. This decentralized computer system (data processing system) can be advantageously designed differently from a computer system (data processing system) used to process information supplied by current measuring devices. This enables redundancy in the processing of temperature and current values.

[0027] An embodiment of the invention is shown schematically in a drawing below and described in more detail thereafter. The drawing shows... Figure 1 is a perspective view of an electrical power transmission facility with a decentralized data processing system, Figure 2 is a representation of the determined measured values ​​ / a determined forecast for the course of a temperature load.

[0028] The Figure 1Figure 1 shows a first electrical power transmission device 1 and a second electrical power transmission device 2 in perspective view. The first electrical power transmission device 1 is a so-called outdoor circuit breaker. This outdoor circuit breaker is three-pole, meaning it has a first switching pole 1a, a second switching pole 1b, and a third switching pole 1c. Each of the switching poles 1a, 1b, 1c contains an internal interrupter unit, which serves to interrupt a current path. The interrupter units can be electrically connected via terminal fittings 3. For this purpose, the terminal fittings 3 are arranged on electrically insulating housings of the respective switch poles 1a, 1b, 1c. The switch poles 1a, 1b, 1c of the first electrical power transmission device 1 are arranged on a support frame 4.The support frame 4 holds the switch poles 1a, 1b, 1c at intervals from a foundation. A secondary cabinet 5 is attached to the support frame 4, housing secondary modules and a drive unit. The drive unit actuates the switching contacts of the switch poles 1a, 1b, 1c, which are movable relative to each other. Thus, the drive unit initiates a switching operation of the first electrical power transmission device 1. The secondary modules, also located in the secondary cabinet 5, serve, for example, to control, monitor, protect, etc., the first electrical power transmission device 1. These secondary modules can include, for example, control units, monitoring units, interfaces, sensors, etc.

[0029] The second electrical power transmission device 2 is a current transformer with a three-pole configuration. Each of the three current transformer poles, 2a, 2b, 2c, has a supporting insulator 6. An active component 7a, 7b, 7c is electrically insulated and supported by the respective supporting insulator 6 of each current transformer pole 2a, 2b, 2c. Each active component contains a primary current path, which can be electrically connected via connection fittings 3 outside the active component 7a, 7b, 7c. The respective primary current path of each active component 7a, 7b, 7c serves to extract information about an electric current flowing through the primary conductor. For example, a transformer principle can be used for this purpose, in which a transformation from the primary conductor to a secondary winding (not visible in the figure inside the respective active component 7a, 7b, 7c) can be carried out.The measured values ​​determined by the secondary component can be transmitted, for example, via wired or wireless connection to a secondary cabinet 8 located at the base of the respective current transformer pole 2a, 2b, 2c. Corresponding secondary modules can be arranged in the secondary cabinets 8 to further distribute the current flow information supplied by the measuring transformer, for example, via a data network.

[0030] The first electrical power transmission device 1 and the second electrical power transmission device 2 are integrated into an electrical power transmission line and connected in series. The electrical power transmission line is a three-pole electrical power transmission line used for transmitting a three-phase alternating voltage. The electrical power transmission line has a first phase conductor 9a, a second phase conductor 9b, and a third phase conductor 9c. Along each of the three phase conductors 9a, 9b, 9c, one of the switching poles 1a, 1b, 1c is arranged, as well as one of the current transformer poles 2a, 2b, 2c. Thus, along each phase conductor 9a, 9b, 9c, an interrupter of a switching pole 1a, 1b, 1c is arranged, followed by a primary conductor of a current transformer pole 2a, 2b, 2c of an active part 7a, 7b, 7c. In the Figure 1The section of the electrical power transmission line shown is an open-air design, meaning that the three phase conductors 9a, 9b, 9c are designed as open-air insulated conductor cables in this section. To enable contact with the first electrical power transmission device 1 and the second electrical power transmission device 2, the phase conductors 9a, 9b, 9c are electrically connected to the respective terminal fittings 3 of the respective switch poles 1a, 1b, 1c and the respective current transformer poles 2a, 2b, 2c.

[0031] The first electrical power transmission device 1 makes it possible to switch the phase conductors 9a, 9b, 9c of the electrical power transmission line, i.e., to interrupt or connect them. With a corresponding current flow on the individual phase conductors 9a, 9b, 9c, the current flowing can be determined by means of the current transformer poles 2a, 2b, 2c of the second electrical power transmission device 2. Conversely, if the phase conductors 9a, 9b, 9c are interrupted, the interruption of the electrical current can be detected by the interrupting units of the switching poles 1a, 1b, 1c.

[0032] To obtain further information about the condition of the first and second electrical power transmission devices 2, temperature sensors 10 are arranged at each of the switching poles 1a, 1b, 1c and at each of the current transformer poles 2a, 2b, 2c. The temperature sensors 10 serve to detect the temperature of the respective phase conductors 9a, 9b, 9c, which form part of the first and second electrical power transmission devices 1 and 2, respectively. The connection fittings 3 are used to position the temperature sensors 10. The connection fittings 3 provide a sufficiently stable mechanical support to hold the temperature sensors 10. Furthermore, the connection fittings 3 are part of the phase conductors 9a, 9b, 9c and are therefore subject to an electric current flowing through them, resulting in an electrical heating effect.The position of the temperature sensors 10 on the connection fittings 3 is chosen such that only the output-side connection fittings 3 of the first electrical power transmission unit 1 or the second electrical power transmission unit 2 are used. However, if required, temperature sensors 10 can also be positioned on the input side, or both on the input and output sides.

[0033] The temperature sensors 10 are connected to a decentralized computer system 12 (data processing system) via information channels 11. The temperature sensors 10 can communicate directly with the decentralized computer system 12. However, it is also possible to provide local switching devices, for example, a local switching device for the first electrical power transmission device 1 and a local switching device for the second electrical power transmission device 2, which temporarily store, format, and transfer the information (data) supplied by the temperature sensors 10 into a specific data protocol, add further information such as ambient temperature information, information about the position of the switching device or the temperature sensors 10, and supplement the information supplied by the temperature sensors 10.

[0034] The decentralized computer system 12, which receives the data supplied directly or indirectly via a switching device by the temperature sensors 10, can also process this data. In addition to the decentralized computer system 12, a further computer system 12a can be provided. The further computer system 12a (further data processing system) can exchange information with the decentralized computer system 12. The further decentralized computer system 12a can be part of the decentralized computer system 12 and can be completely identical to it. However, it can also be provided that the further decentralized computer system 12 is implemented completely independently of the decentralized computer system 12, so that the information supplied by the current transformer poles 2a, 2b, 2c of the second electrical power transmission device 2 regarding a current flow is processed independently.

[0035] The decentralized computer system 12 can, for example, have a display device in which, for example, a graphical representation of the measured values ​​of the temperature sensors 10 or of predicted temperatures can be displayed.

[0036] In the Figure 2A corresponding diagram is shown, in which a temperature T in degrees Celsius is plotted against time t. A first temperature threshold T1 and a second temperature threshold T2 are defined. The first temperature threshold T1 represents a temperature value that reflects a high thermal load on one of the phase conductors 9a, 9b, 9c. Experience shows that this temperature is primarily influenced by current flow on the conductors. Even with external influences on the conductor temperatures, such as solar radiation, these typically occur uniformly at the first and second electrical power transmission devices 1 and 2, respectively. Therefore, it is also possible to respond to thermal overloads that are not solely caused by current flow on the phase conductors 9a, 9b, 9c.The second temperature threshold T2 represents a temperature at the phase conductors 9a, 9b, 9c that is unacceptable and requires action. For example, it may be necessary to disconnect the phase conductors 9a, 9b, 9c by the first electrical power transmission device 1. In the . Figure 2Three graphs of three temperature profiles are shown. The first temperature profile 13a depicts the temperature profile at the first phase conductor 9a at the first switching terminal 1a. The second temperature profile 13b depicts the temperature profile of the second phase conductor 9b at the second switching terminal 1b of the first electrical power transmission device 1. The third temperature profile 13c depicts the temperature profile of the third phase conductor 9c at the third switching terminal 1c of the first electrical power transmission device 1. A representation of the temperature profiles, which are based on the temperature sensors 10 at the current transformer terminals 2a, 2b, 2c of the second electrical power transmission device 2, was shown in the Figure 2 Omitted. These temperature profiles can be shown in a separate diagram or supplemented in the diagram according to... Figure 2 be displayed.

[0037] As can be seen from the graphs of the first temperature profile 13a and the second temperature profile 13b, the thermal behavior at the first switching pole 1a and the second switching pole 1b of the first electrical power transmission device 1 is approximately identical up to a certain time ty. The third temperature profile 13c at the third switching pole 1c of the first electrical power transmission device 1 shows a different behavior. The temperature level at the third switching pole 1c is consistently higher than the temperature levels at the first switching pole 1a and the second switching pole 1b. There is a temperature deviation between the temperature profiles 13a, 13b, and 13c. However, this deviation remains within a tolerance band until time t0. At time t0, the temperature deviation exceeds the tolerance band, and a signal can be generated.Accordingly, at time t1, the temperature at the third switching terminal 1c reaches the first temperature threshold T1. Upon reaching the first temperature threshold T1, a warning (signal) can be issued. At time tx, a more pronounced increase in the third temperature profile 13c is observed. Up to time ty, the temperature rises significantly more steeply than in the preceding time periods. Based on this steep increase, a forecast of the third temperature profile 13c (dotted line) can be made, and in this forecast, the second temperature threshold T2 is reached at time t2. Subsequently, based on the forecast, the third temperature profile 13c may exhibit a more moderate increase.

[0038] Analogous to the forecast of the third temperature profile 13c, the first temperature profile 13a and the second temperature profile 13b can be predicted in a forecast for a period after ty.

[0039] Both in the range of measured values ​​of temperature profiles 13a, 13b, 13c and in the range of temperature profiles 13a, 13b, 13c. Is there a deviation between the approximately similar first temperature profile 13a and the second temperature profile 13b with respect to the third temperature profile 13c? This deviation is in the Figure 2 represented by a diamond-shaped hatching pattern. Accordingly, at any given time t, it is possible to determine the temperature deviation of the first, second, and third temperature profiles 13a, 13b, and 13c for both the measured and the predicted values. Upon reaching or exceeding a predefined tolerance band (here at time t0), a corresponding signal can be triggered. For example, this can be done by displaying a corresponding hatching pattern, as shown in the graphic representation according to... Figure 2A color change, etc., will be shown. If necessary, appropriate recommendations for action can also be given.

[0040] To verify the observed deviation and its signaling, additional information obtained from the time series can be used. For example, the steep increase in the interval tx-ty and the associated deviation of the third temperature profile 13c from the first and second temperature profiles 13a, 13b can be used to verify the relevance of the deviation. Furthermore, information on the current flow on the phase conductors 9a, 9b, 9c can be used to verify the deviation. For example, the information on the current flow on the respective phase conductors 9a, 9b, 9c determined by the second electrical power transmission device 2 in the individual current transformer poles 2a, 2b, 2c can be used. If all three phase conductors 9a, 9b, 9c have a similar load, i.e.,If an approximately uniform current flow is present, but a deviation in the temperature distribution across the three phase conductors 9a, 9b, and 9c has been detected, the presence of a fault can be inferred. Therefore, the presence of a fault can be verified by evaluating the current loads.

[0041] Conversely, if the temperature deviations with respect to a current load on the individual phase conductors 9a, 9b, 9c are consistent, the signal can be discarded before it is issued.

Claims

1. A monitoring method for an electric energy transfer device (1, 2) comprising a first phase conductor (9a) and a second phase conductor (9b), wherein a temperature (13a) of the first phase conductor (9a) and a temperature (13b) of the second phase conductor (9b) are determined simultaneously, the determined temperature (13a) of the first phase conductor (9a) is compared with the determined temperature (13b) of the second phase conductor (9b), and if there is a deviation of the determined temperatures (13a, 13b) from one another, signalling is performed, characterised in that the deviation is verified by a rate of change of a determined temperature (13a, 13b) of a phase conductor (9a, 9b) and / or the deviation of the determined temperatures (13a, 13b).

2. The monitoring method according to claim 1, characterised in that a first electric current loading the first phase conductor (9a) and a second electric current loading the second phase conductor (9b) are determined simultaneously, the determined electric currents are compared and, if there is a deviation of the determined currents from one another, the deviation of the determined temperatures (13a, 13b) is verified.

3. The monitoring method according to claim 2, characterised in that a deviation of temperature and a deviation of current of the respective phase conductors (9a, 9b) are tested for a similarity of the deviation of temperature and the deviation of current.

4. The monitoring method according to any one of claims 1 to 3, characterised in that a test for a deviation is performed upon exceeding a preset tolerance band.

5. The monitoring method according to any one of claims 1 to 4, characterised in that a prognosis for the course of the temperature load of at least one of the phase conductors is made based on determined measured values, in particular for temperatures (13a, 13b) and / or currents.

6. The monitoring method according to any one of claims 1 to 5, characterised in that the method steps are executed in a decentralised data processing system (12).

7. A computer programme product which, when the programme runs on a data processing system, is designed to execute a method according to any one of claims 1 to 6.

8. An electric energy transfer device (1, 2) comprising a first phase conductor (9a) and a second phase conductor (9b), and a first current measuring device (7a) for the first phase conductor (9a) and a second current measuring device (7b) for the second phase conductor (9b), wherein the first phase conductor (9a) has a first temperature sensor (10), and the second phase conductor (9b) has a second temperature sensor (10), characterised in that at least the temperature sensors (10) are connected to a decentralised computer system (12) which is configured to execute the method according to any one of claims 1 to 6.