Patent Application
20240372364
The present invention regards the sector of lines for the distribution of electrical energy and, more particularly, the sector of diagnostics for said lines.
Currently, methods and systems relating to lines for the distribution of electrical energy are known.
Said methods and systems have a series of drawbacks.
A first drawback is due to the fact that they do not allow to execute an accurate diagnostics in relation to the line as a whole and/or in relation to pieces of the same line and/or in relation to one or more of the devices connected to it, such as, for example, performing a calibration of the voltage reduction devices during the operation of the line, that is, with the line energized.
A second drawback is due to the fact that they require the use in the line of multiple devices and multiple apparatuses with consequent set up and maintenance costs.
A third drawback is due to the fact that they do not allow to modify an existing line system, in which it is not possible to carry out the diagnostics of the devices, in a line system in which it is possible to carry out the diagnostics of the pre-existing line and/or the diagnostics of the related apparatuses already present, such as, for example, obtaining a line in which it is possible to perform the calibration of the voltage reduction apparatuses, without, for example, having to install measurement voltage transformers in each of the individual secondary substations.
The purpose of the present invention is therefore to solve the aforementioned drawbacks.
The invention, which is characterized by the claims, solves the problem of creating a METHOD relating to a system for an electric power distribution line comprising: a first distribution line in medium voltage; a first secondary substation; at least one second secondary substation; n h said first secondary substation comprises: a first medium voltage conductor as input conductor in said first secondary substation and connected to the aforementioned first distribution line; a first current transformer connected to the first line of medium voltage at a point between the first secondary substation and the second secondary substation and able to detect the current along the aforementioned first line of medium voltage; a measuring voltage transformer connected to said first conductor and able to measure the voltage entering the first secondary substation; and a first PMU connected to the output of said first current transformer and to the output of said first measurement voltage transformer; n which said second secondary substation comprises: a second medium voltage conductor as input conductor in said second secondary substation and connected to the aforementioned first distribution line; a first voltage reducing apparatus connected to said second medium voltage inlet conductor; and a second PMU connected to the outlet of said second voltage reduction apparatus located in said second secondary substation; in which said system comprises: a receiving_processing unit suitable for receiving and processing the data transmitted by the first PMU located in the first secondary substation and the data transmitted by the second PMU located in the second secondary substation; in which said method is characterized by the fact that it comprises the following operations: m.1a)_to detect by the first PMU located in the first secondary substation and at certain instants of time the values of the current along the first distribution line detected by the first current transformer located in the same first secondary substation and transmitting the relative data with relative time references to the receiving-processing unit; m.1b)_to detect by the first PMU located in the first secondary substation and at certain instants of time which are the same instants of time of the previous point m.1a) the voltage values at the output of the transformer measuring voltage located in the same first secondary substation and transmitting the relative data with relative time references to the receiving_processing unit; m.1c)_to detect by the second PMU located in the second secondary substation and in certain instants of time which are the same instants of time of the previous point m.1a) the voltage values at the output of said first voltage reduction apparatus located in said second secondary substation and transmitting the relative data with relative time references to the receiving-processing unit; m.1d)_to identify and to by means of said receiving_processing unit among the data received at least a first instant in time in which the value of the current relative to the first line detected by means of the current transformer located in the first secondary substation is lower than a first predetermined threshold value; m.1e)_to process by means of said receiving_processing unit one or more data received from the same receiving_processing unit and regarding said first instant of time in order to perform a calibration in relation to the first voltage reduction apparatus located in the second secondary substation.
The invention, which is characterized by the claims, solves the problem of creating a SYSTEM relating to a line for the distribution of electrical energy comprising a first distribution line in medium voltage, a first secondary substation and at least one second secondary substation; in which said system is characterized by the fact that said first secondary substation comprises: a first medium voltage conductor as input conductor in said first secondary substation and connected to the aforementioned first distribution line; a first current transformer connected to the first line of medium voltage in a zone between the first secondary substation and the second secondary substation and able to detect the current along the aforementioned first line of medium voltage; a measuring voltage transformer connected to said first conductor and able to measure the voltage entering the first secondary substation; and a first PMU connected to the output of said first current transformer and to the output of said first measurement voltage transformer; by the fact that said second secondary substation comprises: a second medium voltage conductor as input conductor in said second secondary substation and connected to the aforementioned first distribution line; a first voltage reducing apparatus connected to said second medium voltage inlet conductor; and a second PMU connected to the outlet of said second voltage reduction apparatus located in said second secondary substation; by the fact to comprises a receiving_processing unit able to receive and process the data transmitted by the first PMU located in the first secondary substation and the data transmitted by the second PMU located in the second secondary substation; and by the fact that said system is configured to perform the following operations: s.1a)_by the first PMU located in the first secondary substation to detect at certain instants of time the values of the current along the first distribution line detected by the first current transformer located in the same first secondary substation and transmitting the relative data with relative time references to the receiving-processing unit; s.1b)_by the first PMU located in the first secondary substation to detect at certain instants of time which are the same instants of time of the previous point s.1a) the voltage values at the output of the transformer measuring voltage located in the same first secondary substation and transmitting the relative data with relative time references to the receiving_processing unit; s.1c)_by the second PMU located in the second secondary substation to detect in certain instants of time which are the same instants of time of the previous point s.1a) the voltage values at the output of said first voltage reduction apparatus located in said second secondary substation and transmitting the relative data with relative time references to the receiving-processing unit; s.1d)_by means of said receiving_processing unit to identify and to select among the data received at least a first instant in time in which the value of the current relative to the first line detected by means of the current transformer located in the first secondary substation is lower than a first predetermined threshold value; s.1e)__by means of said receiving_processing unit to process one or more data received from the same receiving_processing unit and regarding said first instant of time in order to perform a calibration in relation to the first voltage reduction apparatus located in the second secondary substation.
Further characteristics and advantages of the present invention will be more evident from the following description of some of its preferred practical embodiments, given here purely by way of non-limiting example, made with reference to the figures of the attached drawings in which:
With reference to the description of the method and of the system below, the devices called “PMU”, ref. 151 and 251, are known devices whose technical name in English, not yet clear as a translation into Italian, would be “Phasor_Measurement_Units” (acronym PMU).
These PMU are devices that using a common time source for synchronization and measure and/or detect voltage phasors data/values and/or measure and/or detect current data/phasors and/or other parameters, to then transmit the data/values relating to the measurements and/or surveys performed, in technical terms the “phasors”, for example relating to the voltage and/or current at nominal grid frequency (for example 50 Hz or 60 Hz), with associated date and time, with a very high temporal resolution, up to 120 measurements per second and with a temporal resolution of the order of tens of nanoseconds.
In this context, in relation to the protection conferred by the present invention, it means that in relation to the said one or more “PMU”, this unit can also be replaced with other means able to perform the same function with respect to the function that will be described in the description, without departing from the inventive concepts protected by the present invention.
Always with reference to the descriptions below relating to the method and the system, and always in relation to the protection conferred by this invention, it is understood that in relation to the device “receiving_processing unit”, ref. UR, said device may also be replaced by other means capable of performing the same function as specified in the description, without departing from the inventive concepts protected by the present invention.
With reference to
With reference to
With reference to the first line for the distribution of electricity L1.MT, one or more secondary substations can be connected to it, such as, for example, as illustrated in
With reference to
With reference to
Again with reference to
With reference to the system described above, the method object of the present invention comprises the following operations: m.1a)_to detect by the first PMU 151 located in the first secondary substation CS.100 and at certain instants of time the values of the current along the first distribution line L1.MT detected by the first current transformer 116 located in the same first secondary substation CS.100, more particularly the current values of the line section L1.MT comprised between the first secondary cabin CS.100 and the second secondary cabin CS.200, and transmitting the relative data with relative time references to the receiving-processing unit UR; m.1b)_to detect by the first PMU 151 located in the first secondary substation CS.100 and at certain instants of time which are the same instants of time of the previous point m.1a) the voltage values at the output of the transformer measuring voltage 120 located in the same first secondary substation CS.100 and transmitting the relative data with relative time references to the receiving_processing unit UR; m.1c)_to detect by the second PMU 251 located in the second secondary substation CS.200 and in certain instants of time which are the same instants of time of the previous point m.1a) the voltage values at the output of said first voltage reduction apparatus 230 located in said second secondary substation CS.200 and transmitting the relative data with relative time references to the receiving-processing unit UR; m.1d)__ to identify and to select by means of said receiving_processing unit UR among the data received at least a first instant in time in which the value of the current relative to the first line L1.MT detected by means of the current transformer 116 located in the first secondary substation CS.100 is lower than a first predetermined threshold value; m.1e)_to process by means of said receiving_processing unit UR one or more data received from the same receiving_processing unit UR and regarding said first instant of time in order to perform a calibration in relation to the first voltage reduction apparatus 230 located in the second secondary substation CS.200.
Again referring to the system described above, the method object of the present invention may preferably also include the following operations: m.2a)_to store by means of the receiving_processing unit UR the data transmitted by the first PMU 151 and by the second PMU 251; m.2b)_to identify and to select by means of said receiving_processing unit UR among the data received at least a first instant of time in which the value of the current relative to the first line L1.MT detected by the current transformer 116 located in the first secondary substation CS.100 is lower than a predetermined first threshold value; m.2c)_to identify by means of said receiving_processing unit UR among the received data the data concerning the output voltage with respect to the measurement voltage transformer 120 located in the first secondary substation CS.100 in the same first instant time identified and selected in point m.2b) above; n.2d)_to identify by means of said receiving_processing unit UR, among the received data, the data concerning the output voltage with respect to the first voltage reduction apparatus 230 located in the second secondary substation CS.200 in the same first instant of time identified and selected in point m.2b) above; m2e)_to process by the receiving_processing unit UR the data identified by the previous point m.2c) and point m.2d) relating said first instant of time in order to perform a calibration in relation to the first voltage reduction apparatus 230 located in the second secondary substation CS.200.
Again referring to the system described above, the method object of the present invention can optionally also comprise the following operation: m.3a)_to perform by means of the receiving_processing unit UR a comparison between at least a first value concerning the outlet voltage from said second voltage reduction apparatus 230 located in the second secondary substation CS.200 with at least a second value relating to the outlet voltage of said measurement voltage transformer 120 located in the first secondary substation CS.200, in which said first value and said second value are related to the same instant of time, as for example a first instant of time as specified above, in which the value of the current detected by the first current transformer 116 is lower than a pre-fixed first threshold value.
With reference to the first predetermined threshold value mentioned in this description, see in particular but not exclusively the above points m.1d) and m.2b), it is preferably equal to zero, or, always preferably, equal to a value such as to have an effect due to the voltage drop on the first line due to the current flowing in the first line, having a negligible amount. This current value can for example be determined on the basis of the length of the first line L1.MT.
With reference to
With reference to
With reference to the first line L1.MT for the distribution of electricity, one or more secondary substations can be connected to it, such as, for example, as illustrated in
With reference to
With reference to
Again with reference to
With reference to the system described above, it can be configured to perform the following operations: s.1a)_by the first PMU 151 located in the first secondary substation CS.100 to detect at certain instants of time the values of the current along the first distribution line L1.MT detected by the first current transformer 116 located in the same first secondary substation CS.100, more particularly in the section of line L1.MT between the first secondary substation CS.100 and the second secondary substation CS.200, and transmitting the relative data with relative time references to the receiving-processing unit UR; s.1b)_by the first PMU 151 located in the first secondary substation CS.100 to detect at certain instants of time which are the same instants of time of the previous point s.1a) the voltage values at the output of the transformer measuring voltage 120 located in the same first secondary substation CS.100 and transmitting the relative data with relative time references to the receiving_processing unit UR; s.1c)_by the second PMU 251 located in the second secondary substation CS.200 to detect in certain instants of time which are the same instants of time of the previous point s.1a) the voltage values at the output of said first voltage reduction apparatus 230 located in said second secondary substation CS.200 and transmitting the relative data with relative time references to the receiving-processing unit UR; s.1d)_by means of said receiving_processing unit UR to identify and to select among the data received at least a first instant in time in which the value of the current relative to the first line L1.MT detected by means of the current transformer 116 located in the first secondary substation CS.100 is lower than a first predetermined threshold value; s.1e)_by means of said receiving_processing unit UR to process one or more data received from the same receiving_processing unit UR and regarding said first instant of time in order to perform a calibration in relation to the first voltage reduction apparatus 230 located in the second secondary substation CS.200.
Again with reference to the system described above, if desired, it can be configured to perform also the following operations: s.2a)_by means of the receiving_processing unit UR storing the data transmitted by the first PMU 151 and from the second PMU 251; s.2b) by means of said receiving_processing unit UR identify and select from the received data at least a first instant of time in which the current value relating to the first line L1.MT detected by the current transformer 116 located in the first secondary substation CS.100 is lower than a predetermined first threshold value; s.2c)_by means of said receiving_processing unit UR identify among the received data the data concerning the output voltage with respect to the measurement voltage transformer 120 located in the first secondary substation CS.100 in the same first instant of time identified and selected in above point s.2b); s.2d) by means of said receiving_processing unit UR identify among the received data the data concerning the output voltage with respect to the first voltage reduction apparatus 230 located in the second secondary substation CS.200 in the same first instant of time identified and selected in above point s.2b); s.2n)_by means of the receiving_processing unit UR to process the data identified in the above point s.2c) and point s.2d) regarding said first instant of time in order to perform a calibration in relation to the first voltage reduction apparatus 230 located in the second secondary substation CS.200.
Always the system described above can also be configured to perform the following operation: m3a)_to perform by means of the receiving_processing unit UR a comparison between at least a first value concerning the outlet voltage from said second voltage reduction apparatus 230 located in the second secondary substation CS.200 with at least a second value relating to the outlet voltage of said measurement voltage transformer 120 located in the first secondary substation CS.200, in which said first value and said second value are related to the same instant of time, as for example, a first instant in time as specified above, in which the value of the current detected by the first current transformer 116 is lower than a given first predetermined threshold value. With reference to the first predetermined threshold value mentioned in the present description, see in particular points s.1d) and s.2b), it is preferably equal to zero, or, always preferably, equal to a value such as to have an effect due to the voltage drop on the first line due to the current flowing in the first line itself, having a negligible amount. This current value can for example be determined on the basis of the length of the first line L1.MT.
With reference to the above description and examples, in relation to the calibration of one or more voltage reduction apparatuses 120/130/230/320, preferably, the method and/or system described above is particularly effective when the value of the current relative to the first line L1.MT detected by means of the current transformer 16 located in the primary substation CP is lower than a given first predetermined threshold value and, preferably, when said first threshold value is equal to zero (optimal value).
With reference to said first threshold value of the current not to be exceeded detected by the current transformer 116, by way of non-limiting example, it can be determined in correlation with the components that are applied along the line L1.MT and, in any case, this first threshold value must have a measure such as to have an effect due to the voltage drop on the line L1.MT due to the effect of the current flowing in the line L1.MT having a negligible amount.
According to a first form of determination, if the value of said voltage detected by means of the precision TV 120 is equal to 100 kV effective Volt and if in the first secondary substation CS.100 there is a voltage reduction apparatus 130 as a capacitive divider type having the following characteristics, rated voltage 10 kV and accuracy class 0.5 (i.e. maximum ratio error 0.5% of the rated voltage and maximum phase error equal to 0.6 crad in the range 80%-120% of the rated voltage-values in accordance with the reference standard IEC 61869-1), said first threshold value of the current that not to be exceeded will be such as not to cause a voltage drop along the line not exceeding a fraction of the ratio error associated with accuracy class 0.5, i.e. 0.5% of 10 kV=50V rms. It is common among calibration laboratories to consider this fraction of the ratio error variable between ⅓ and ⅕ of the accuracy class, that is, in the example cited, between 0.1% and 0.2% which, in absolute value, corresponds at an interval between 10V and 20V.
Therefore, the drop along the line caused by the current must not exceed, for example, 20V. If, according to the tables of the characteristics of the medium voltage cables used on the market, a series resistance of the cable of 0.2 ohm/km is assumed, with reference to 10 km of length the current must be less than 10 A in order not to exceed 20V of drop.
In this context, this first predetermined threshold value is preferably a value such as to have an effect due to the voltage drop on the first line L1.MT having an entity equal to or less than ⅓ of the ratio error associated with the accuracy class of a voltage reduction apparatus, for example 130, to be calibrated.
By means of the method and/or system object of the present invention it is possible to perform a calibration in relation to one or more voltage reduction apparatuses located in a secondary substation or in other secondary substations, solving the above mentioned problems.
Furthermore, again by means of the method and/or system object of the present invention, it is possible to modify existing grid systems, such as for example the systems illustrated in
The descriptions of the above method and of the above system are given by way of example only and not by way of limitation and, therefore, it is clear that said method and said system may be subject to any changes or variations suggested by the practice and their implement or use and, in any event, within the scope of the following claims, in which this claims form an additional and/or complementary part for this description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102021000024532 | Sep 2021 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IT2022/000048 | 9/15/2022 | WO |
