GB2543754A - Device for measuring the voltage of a busbar - Google Patents
Device for measuring the voltage of a busbar Download PDFInfo
- Publication number
- GB2543754A GB2543754A GB1518686.9A GB201518686A GB2543754A GB 2543754 A GB2543754 A GB 2543754A GB 201518686 A GB201518686 A GB 201518686A GB 2543754 A GB2543754 A GB 2543754A
- Authority
- GB
- United Kingdom
- Prior art keywords
- voltage
- conductor
- capacitor
- measuring
- capacitor plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/04—Voltage dividers
- G01R15/06—Voltage dividers having reactive components, e.g. capacitive transformer
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/142—Arrangements for simultaneous measurements of several parameters employing techniques covered by groups G01R15/14 - G01R15/26
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/16—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using capacitive devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/32—Compensating for temperature change
Abstract
The invention relates to a combination of a conductor 2, which may be a busbar, and a device for measuring the AC voltage in the conductor. The device comprises an insulation layer 3 arranged on the conductor and a capacitor plate arranged on the insulation layer 4, the plate being at a fixed distance from the conductor. Together the capacitor plate and the conductor form a first capacitor. The device also comprises a second capacitor 6 arranged electrically between the capacitor plate and ground to provide a capacitive voltage divider with the first capacitor. The device has means for measuring the voltage at the capacitor plate and means for measuring the frequency of the voltage in the conductor. The device also has means for calculating the AC voltage in the conductor based on the capacities of the first and second capacitors, the measured voltage and the measured frequency.
Description
Device for measuring the voltage of a busbar
The invention relates to a combination of a conductor, such as a busbar, and a device for measuring the AC voltage in the conductor, which device comprises: - an insulation layer arranged on the conductor; - a capacitor plate arranged on the insulation layer to position the capacitor plate at a fixed distance from the conductor to form a first capacitor; - a second capacitor arranged electrically between the capacitor plate and ground to provide a capacitive voltage divider with the first capacitor; and - means for measuring the voltage at the capacitor plate .
Such a combination is for example known from US 5017859. Capacitive voltage dividers are known to reduce the voltage of the conductor to a level, which is more suitable to be measured with conventional measurement equipment. The use of capacitors allows one to measure the voltage without any leakage of current. A resistive voltage divider could also be used for measuring the voltage of a conductor, but with high voltages, the components become considerably large and current will leak via the resistors.
The use of a capacitive voltage divider allows one to use smaller components, as no current will flow through the capacitors. However, the capacitors have an impedance which is dependent on the frequency of the voltage to be measured. As long as the frequency is virtually constant, the voltage in the conductor can be measured accurately. However, if the frequency varies, the accuracy of the measurements will vary.
Furthermore, with the combination according to US 5017859, the distance of the capacitor plate to the conductor could vary due to manufacturing tolerances or due to heating of the combination, which causes the insulation layer to expand. As a result the capacity of the first capacitor will change having an adverse effect on the voltage measurement.
It is an object of the invention to reduce or even remove the above mentioned disadvantages.
This object is achieved according to the invention with a combination according to the preamble, which is characterized by: - means for measuring the frequency of the voltage in the conductor; and - means for calculating the AC voltage in the conductor based on the capacities of the first and second capacitors, the measured voltage and the measured frequency.
Because the frequency of the voltage in the conductor is also measured, one can take into account the changes in the capacitive voltage divider due to any frequency changes .
The means for calculating the AC voltage in the conductor will first determine, based on the known capacity of the first and second capacitors and the measured frequency, what the capacitive reactance of each capacitor is. Similar equations can be used for the capacitive reactance as for resistors. So, with the measured voltage at the capacitor plate and the ratio between both capacitive reactances of the two capacitors, one can accurately calculate the AC voltage in the conductor.
In a preferred embodiment of the combination according to the invention the means for calculating the AC voltage in the conductor comprise a microcontroller with an analog to digital converter input connected via a low pass filter, precision rectifier to the capacitor plate.
Calculations can be quickly and accurately done by a microcontroller. However, the AC voltage needs to be rectified, such that the voltage is only of a changing positive value, which can then be fed to low pass filter and then to the analog to digital converter for further processing by the microcontroller.
Another preferred embodiment of the combination according to the invention, further comprises a temperature sensor for measuring the temperature of the insulation layer and wherein the means for calculating the AC voltage in the conductor take into account the measured temperature.
When the temperature of the insulation layer changes, the insulation layer will typically expand or compress, such that the distance of the capacitor plate to the conductor will change. Especially in high voltage applications, in which the insulation layer will typically be an epoxy resin, temperatures can rise substantially and expansion of the epoxy resin will be considerable. This will cause the capacity of the first capacitor to reduce when the temperature rises.
In order to take the changes in the capacity of the first capacitor into account, the temperature is measured and based on an equation or based on calibration data, the changes in the capacity of the first capacitor will be taken into account based on the measured temperature.
Yet another embodiment of the combination according to the invention, further comprises storage means for storing calibration data and wherein the means for calculating the AC voltage in the conductor take into account the calibration data out of the storage means.
Although the manufacturing process could be very accurate, there will still be some small differences between similar combinations. In order to further increase the accuracy of the calculation of the AC voltage in the conductor, a combination can be tested with known voltages directly after manufacturing. The resulting data can be stored in the storing means, such that this calibration data can be taken into account during the calculation of the AC voltage in the conductor.
In a preferred embodiment of the combination according to the invention, the combination is a high voltage bushing.
These and other features of the invention will be elucidated in conjunction with the accompanying drawing.
Figure 1 shows a schematic view of an embodiment of the combination according to the invention. A bushing 1 is shown in figure 1 having a conductor 2 embedded in an epoxy resin 3. A capacitor plate 4 is concentrically around the conductor 2 with the epoxy resin 3 serving as insulation layer in between. Furthermore, a temperature sensor 5 is embedded near capacitor plate 4 in the epoxy resin 3 for measuring the temperature of the epoxy resin 3.
The conductor 2 and the capacitor plate 4 embody a first capacitor, which is connected to a second capacitor 6, which in turn is connected to ground 7. The first capacitor 2, 4 and the second capacitor 6 provide a capacitive voltage divider.
The voltage of the capacitor plate 4 is first fed to a buffer and low pass filter 8 to protect the electronics behind the buffer and low pass filter 8, as well to filter any high frequency noise.
The voltage of the capacitor plate 4 is then fed via a precision full wave rectifier 9 and low pass filter 10 to an analog to digital converter 11 of a microcontroller 12 for converting to a digital value of the measured voltage.
The voltage of the capacitor plate 4 is also fed to a zero crossing detector type voltage converter 13, which feeds to the microcontroller 12for frequency measurement.
Also the signal of the temperature sensor 5 is fed via a low pass filter 14 and an amplifier 15 to the microcontroller 12 for measuring and taking into account the epoxy inner temperature.
Taking into account the epoxy temperature, the microcontroller 12 can calculate based on the digital value of the measured voltage on the capacitor plate 4, the measured frequency and the known capacities of the first capacitor 2, 4 and the second capacitor 6, what the real voltage in the conductor 2 is.
Using the temperature measurements of the temperature sensor 5, the microcontroller 12 can calculates the change in the first capacitor 2, 4 capacity due to the expansion or compression of the epoxy resin for any change in the epoxy inner temperature using a software algorithm and the stored pre-test data in the microcontroller. The microcontroller 12 adjusts the measured voltage as per the new calculated first capacitor 2,4 capacity using the software algorithm for accurate voltage measurement.
Claims (6)
1. Combination of a conductor, such as a busbar, and a device for measuring the AC voltage in the conductor, which device comprises: - an insulation layer arranged on the conductor; - a capacitor plate arranged on the insulation layer to position the capacitor plate at a fixed distance from the conductor to form a first capacitor; - a second capacitor arranged electrically between the capacitor plate and ground to provide a capacitive voltage divider with the first capacitor; and - means for measuring the voltage at the capacitor plate, characterized by - means for measuring the frequency of the voltage in the conductor; and - means for calculating the AC voltage in the conductor based on the capacities of the first and second capacitors, the measured voltage and the measured frequency.
2. Combination according to claim 1, wherein the means for calculating the AC voltage in the conductor comprise a microcontroller with an analog-to-digital converter input connected via a low pass filter, precision full wave rectifier to the capacitor plate.
3. Combination according to claim 1 or 2, further comprising a temperature sensor for measuring the temperature of the insulation layer and wherein the means for calculating the AC voltage in the conductor take into account the measured temperature .
4. Combination according to any of the preceding claims, further comprising storage means for storing calibration data and wherein the means for calculating the AC voltage in the conductor take into account the calibration data out of the storage means.
5. Combination according to any of the preceding claims, wherein the combination is a high voltage bushing.
6. Combination according to any of the preceding claims 3-5, wherein the means for calculating the AC voltage use the measured frequency and the measured temperature in the insulation layer at each voltage calculation.
Priority Applications (10)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1518686.9A GB2543754A (en) | 2015-10-21 | 2015-10-21 | Device for measuring the voltage of a busbar |
| AU2016295890A AU2016295890A1 (en) | 2015-07-20 | 2016-06-28 | System for measuring the voltage of a busbar |
| PCT/EP2016/065070 WO2017012837A1 (en) | 2015-07-20 | 2016-06-28 | System for measuring the voltage of a busbar |
| US15/745,718 US10845390B2 (en) | 2015-07-20 | 2016-06-28 | System for measuring the voltage of a busbar |
| EP16736814.1A EP3325983B1 (en) | 2015-07-20 | 2016-06-28 | System for measuring the voltage of a conductor |
| JP2018502730A JP6768784B2 (en) | 2015-07-20 | 2016-06-28 | System for measuring busbar voltage |
| PL16736814T PL3325983T3 (en) | 2015-07-20 | 2016-06-28 | System for measuring the voltage of a conductor |
| BR112018000987A BR112018000987A2 (en) | 2015-07-20 | 2016-06-28 | combination of a conductor |
| ZA2018/01118A ZA201801118B (en) | 2015-07-20 | 2018-02-19 | System for measuring the voltage of a busbar |
| AU2022203050A AU2022203050B2 (en) | 2015-07-20 | 2022-05-06 | System for measuring the voltage of a busbar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1518686.9A GB2543754A (en) | 2015-10-21 | 2015-10-21 | Device for measuring the voltage of a busbar |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201518686D0 GB201518686D0 (en) | 2015-12-02 |
| GB2543754A true GB2543754A (en) | 2017-05-03 |
Family
ID=55131430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1518686.9A Withdrawn GB2543754A (en) | 2015-07-20 | 2015-10-21 | Device for measuring the voltage of a busbar |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2543754A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT201700084428A1 (en) * | 2017-07-25 | 2019-01-25 | Green Seas Ventures Ltd | Method for measuring the voltage value using a capacitive sensor and relative system to implement it |
| WO2021136710A1 (en) * | 2019-12-31 | 2021-07-08 | Eaton Intelligent Power Limited | Sensor part for installation in medium-voltage cable compartments and a device for measuring a voltage in medium-voltage circuits comprising such sensor part |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1471570A (en) * | 1973-12-20 | 1977-04-27 | Siemens Ag | High-voltage monitoring arrangements |
| US20020180459A1 (en) * | 2001-05-31 | 2002-12-05 | Veselin Skendzic | Three-phase voltage sensor with active crosstalk cancellation |
| EP2993480A1 (en) * | 2014-09-04 | 2016-03-09 | 3M Innovative Properties Company | Voltage sensor |
-
2015
- 2015-10-21 GB GB1518686.9A patent/GB2543754A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1471570A (en) * | 1973-12-20 | 1977-04-27 | Siemens Ag | High-voltage monitoring arrangements |
| US20020180459A1 (en) * | 2001-05-31 | 2002-12-05 | Veselin Skendzic | Three-phase voltage sensor with active crosstalk cancellation |
| EP2993480A1 (en) * | 2014-09-04 | 2016-03-09 | 3M Innovative Properties Company | Voltage sensor |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT201700084428A1 (en) * | 2017-07-25 | 2019-01-25 | Green Seas Ventures Ltd | Method for measuring the voltage value using a capacitive sensor and relative system to implement it |
| WO2021136710A1 (en) * | 2019-12-31 | 2021-07-08 | Eaton Intelligent Power Limited | Sensor part for installation in medium-voltage cable compartments and a device for measuring a voltage in medium-voltage circuits comprising such sensor part |
| GB2590987A (en) * | 2019-12-31 | 2021-07-14 | Eaton Intelligent Power Ltd | Sensor part for installation in medium-voltage cable compartments and a device for measuring a voltage in medium-voltage circuits comprising such sensor part |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201518686D0 (en) | 2015-12-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |