Or relating to protection relays

Abstract

A protection relay connection assembly (10) for connecting a current transformer (14) and/or a voltage transformer (16) of an electrical network (12) to a protection relay (18) is provided. The protection relay connection assembly (10) includes a protection relay data acquisition board (20) and a protection relay connector (22). The protection relay data acquisition board (20) includes a first current mating member (24) connectable to a current measurement sensor (28), the current measurement sensor (28) being connectable in use to the protection relay (18) and/or a first voltage mating member (26) connectable to a voltage measurement sensor (30), the voltage measurement sensor (30) being connectable in use to the protection relay (18). The protection relay connector (22) includes a second current mating member (36) connectable to the current transformer (14) and/or a second voltage mating member (38) connectable to the voltage transformer (16). The first current mating member (24) and the second current mating member (36) are selectively mateable with one another to permit a measured current waveform of the electrical network (12) to be transmitted from the current transformer (14) to the protection relay (18). The first voltage mating member (26) and the second voltage mating member (38) are shaped to be selectively mateable with one another to permit a measured voltage waveform of the electrical network (12) to be transmitted from the voltage transformer (16) to the protection relay (18). Wherein the first current mating member (24) is shaped to prevent mating of the first current mating member (24) with the second voltage mating member (38), and the first voltage mating member (26) is shaped to prevent mating of the first voltage mating member (26) with the second current mating member (36).

Claims

1. A protection relay connection assembly for connecting a current transformer and/or a voltage transformer of an electrical network to a protection relay, the protection relay connection assembly comprising: a protection relay data acquisition board including a first current mating member connectable to a current measurement sensor, the current measurement sensor being connectable in use to the protection relay and/or a first voltage mating member connectable to a voltage measurement sensor, the voltage measurement sensor being connectable in use to the protection relay; and a protection relay connector including a second current mating member connectable to the current transformer and/or a second voltage mating member connectable to the voltage transformer, wherein the first current mating member and the second current mating member are shaped to be selectively mateable with one another to permit a measured current waveform of the electrical network to be transmitted from the current transformer to the protection relay and the first voltage mating member and the second voltage mating member are shaped to be selectively mateable with one another to permit a measured voltage waveform of the electrical network to be transmitted from the voltage transformer to the protection relay, and wherein the first current mating member is shaped to prevent mating of the first current mating member with the second voltage mating member, and the first voltage mating member is shaped to prevent mating of the first voltage mating member with the second current mating member, wherein the current measurement sensor is or includes a shunt provided on the protection relay data acquisition board, and/or the voltage measurement sensor is or includes a voltage divider provided on the protection relay data acquisition board.

2. The protection relay connection assembly according to claim 1 wherein the current measurement sensor is connected to the first current mating member and/or the voltage measurement sensor is connected to the first voltage mating member.

3. The protection relay connection assembly according to claim 2 wherein the current measurement sensor is configured to convert a measured current waveform of the electrical network to a representative current waveform to be utilized by the protection relay, and/or wherein the voltage measurement sensor is configured to convert a measured voltage waveform of the electrical network to a representative voltage waveform to be utilized by the protection relay.

4. The protection relay connection assembly according to claim 1 wherein the protection relay data acquisition board includes the first current mating member, the first current mating member has at least one dimension that is larger than the corresponding dimension of the second voltage mating member so as to prevent mating of the first current mating member with the second voltage mating member.

5. The protection relay connection assembly according to claim 1 wherein the protection relay data acquisition board includes the first voltage mating member, the first voltage mating member has at least one dimension that is larger than the corresponding dimension of the second current mating member so as to prevent mating of the first voltage mating member with the second current mating member.

6. The protection relay connection assembly according to claim 1 wherein the protection relay data acquisition board includes the first current mating member, the first current mating member includes a first interference member portion and the second voltage mating member includes a second interference member portion, the first and second interference member portions being shaped to physically interfere with each other to prevent mating of the first current mating member with the second voltage mating member.

7. The protection relay connection assembly according to claim 1 wherein the protection relay data acquisition board includes the first voltage mating member, the first voltage mating member includes a first interference member portion and the second current mating member includes a second interference member portion, the first and second interference member portions being shaped to physically interfere with each other to prevent mating of the first voltage mating member with the second current mating member.

8. The protection relay connection assembly according to claim 1 wherein the first and second current mating members are associated with at least one current visual indicator and/or the first and second voltage mating members are associated with at least one voltage visual indicator, the current and voltage visual indicators differing from one another.

9. The protection relay connection assembly according to claim 1 wherein the protection relay data acquisition board is shaped so that the first current mating member is integrally formed with the protection relay data acquisition board and/or the first voltage mating member is integrally formed with the protection relay data acquisition board.

10. The protection relay connection assembly according to claim 1 wherein the first current mating member has separate poles on opposite faces of the protection relay data acquisition board, each pole being configured to connect to a respective pole of the current transformer of the electrical network and/or the first voltage mating member has separate poles on the protection relay data acquisition board, each pole being configured to connect to a respective pole of the voltage transformer of the electrical network.

11. The protection relay connection assembly according to claim 1 wherein the first current mating member includes first and second mating member portions, each of the first and second mating member portions having a separate pole, each pole being configured to connect to a respective pole of the current transformer of the electrical network and/or the first voltage mating member includes first and second mating member portions, each of the first and second mating member portions having a separate pole, each pole being configured to connect to a respective pole of the voltage transformer of the electrical network.

12. The protection relay connection assembly according to claim 1 wherein the protection relay connector includes a current aperture configured to receive the first current mating members and/or the protection relay connector includes a voltage aperture configured to receive the first voltage mating member.

13. The protection relay connection assembly according to claim 12 wherein the protection relay connector further includes a current mating member cover extending across the current aperture to provide the second current mating member, and/or a voltage mating member cover extending across the voltage aperture to provide the second voltage mating member.

14. A protection apparatus for protecting an electrical network, the protection apparatus comprising: a protection relay connection assembly comprising: a protection relay including a first current mating member connectable to a current measurement sensor, the current measurement sensor being connectable in use to the protection apparatus and/or a first voltage mating member connectable to a voltage measurement sensor, the voltage measurement sensor being connectable in use to the protection apparatus; and a protection relay connector including a second current mating member connectable to a current transformer and/or a second voltage mating member connectable to the a voltage transformer, wherein the first current mating member and the second current mating member are shaped to be selectively mateable with one another to permit a measured current waveform of the electrical network to be transmitted from the current transformer to the protection apparatus and the first voltage mating member and the second voltage mating member are shaped to be selectively mateable with one another to permit a measured voltage waveform of the electrical network to be transmitted from the voltage transformer to the protection apparatus, and wherein the first current mating member is shaped to prevent mating of the first current mating member with the second voltage mating member, and the first voltage mating member is shaped to prevent mating of the first voltage mating member with the second current mating member; and the protection apparatus further comprising one or more inputs electrically coupled with the current and/or voltage measurement sensors, the protection apparatus being configured to be capable of selectively triggering a protective function based on the measured current and/or voltage waveforms to protect the electrical network, wherein the current measurement sensor is or includes a shunt provided on the protection relay, and/or the voltage measurement sensor is or includes a voltage divider provided on the protection relay.

Description

(1) Preferred embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings in which:

(2) FIG. 1 shows a schematic circuit of a protection relay connection assembly according to a first embodiment of the invention in use with an electrical network;

(3) FIG. 2 shows a schematic exploded view of the protection relay connection assembly shown in FIG. 1;

(4) FIG. 3 shows a schematic view of the protection relay data acquisition board shown in FIG. 2; and

(5) FIG. 4 shows a schematic view of the protection relay connector shown in FIG. 2.

(6) The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic form in the interests of clarity and conciseness.

(7) A protection relay connection assembly according to the first embodiment of the invention is designated generally by reference numeral 10 and is shown in FIGS. 1 and 2.

(8) In FIG. 1, the protection relay connection assembly 10 is shown in use with an electrical network 12. In particular, the electrical network 12 includes a primary current transformer 14 connected thereto and a primary voltage transformer 16 connected thereto. The protection relay connection assembly 10 forms part of a protection relay 18.

(9) The protection relay connection assembly 10 includes a protection relay data acquisition board 20 that is electrically coupled to the protection relay 18, and a protection relay connector 22 that is connected to the primary current and voltage transformers 14, 16.

(10) Turning to FIG. 2, the protection relay data acquisition board 20 includes a first current mating member 24 and a first voltage mating member 26. The first current mating member 24 is connected to a current measurement sensor 28 and the first voltage mating member 26 is connected to a voltage measurement sensor 30. The current and voltage measurement sensors 28, 30 provide one or more inputs to the protection relay 18.

(11) The protection relay connector 22 includes a second current mating member 36 and a second voltage mating member 38. The second current mating member 36 is connected to the primary current transformer 14 and the second voltage mating member 38 is connected to the primary voltage transformer 16.

(12) The first and second current mating members 24, 36 are shaped to be mated with one another to permit a measured current waveform from the primary current transformer 14 to be transmitted to the protection relay 18. The first and second voltage mating members 26, 38 are shaped to be mated with one another to permit a measured voltage waveform from the primary voltage transformer 16 to be transmitted to the protection relay 18. The first and second current and voltage mating members 24, 26, 36, 38 are shaped to prevent mating of the first current mating member 24 with the second voltage mating member 38 and mating of the first voltage mating member 26 with the second current mating member 36.

(13) In other embodiments of the invention, the protection relay data acquisition board may include one or more first current mating members only, or one or more first voltage mating members only. Moreover, the protection relay connector may include one or more second current mating members only, or one or more second voltage mating members only.

(14) In the embodiment shown, the protection relay data acquisition board 20 is a printed circuit board (PCB) 40.

(15) Moreover, the current measurement sensor 28 is a shunt 42 which is provided on the PCB 40 and the voltage measurement sensor 30 is a voltage divider 44 also provided in the PCB 40. In this way, the shunt 42 and voltage divider 44 form part of the PCB 40.

(16) Moreover, the shunt 42 converts a current waveform measured from the primary current transformer 14 to a representative current waveform to be utilised by the protection relay 18. In particular, the shunt 42 converts the current waveform of the primary current transformer 14 to a small voltage that is then fed into an analogue-to-digital converter (not shown) present on the PCB 40. The analogue-to-digital converter then produces a digital representation of the current waveform for use by the protection algorithms within the protection relay 18.

(17) The voltage divider 44 converts a voltage waveform measured from the primary voltage transformer 16 to a representative voltage waveform to be utilised by the protection relay 18. In particular, the voltage divider 44 converts the voltage waveform of the primary voltage transformer 16 to a small voltage that is then fed into an analogue-to-digital converter (not shown) present on the PCB 40. The analogue-to-digital converter then produces a digital representation of the voltage waveform for use by the protection algorithms within the protection relay 18.

(18) In other embodiments of the invention (not shown), the current and voltage measurement sensors 28, 30 may take another form such as secondary current and voltage transformers.

(19) As shown in FIG. 2, the PCB 40 itself is shaped to include the first current and voltage mating members 24, 26. In particular, the perimeter 46 of the PCB 40 on one side thereof is shaped so as to have a keying profile 48 that includes the first current and voltage mating members 24, 26.

(20) The keying profile 48 is described in more detail with reference to FIG. 3. In particular, the keying profile 48 forms first and second voltage fingers 50a, 50b which extend from the perimeter 46 of the PCB 40 and are spaced from one another by a voltage spacing perimeter portion 52. The first and second voltage fingers 50a, 50b and voltage perimeter portion 52 define an overall length L.sub.V of the first voltage mating member 26. In this way, the first voltage mating member 26 includes first and second voltage mating member portions 26a, 26b.

(21) Each voltage finger 50a, 50b has separate voltage poles (not shown) to provide the voltage connection to the primary voltage transformer 16. The voltage poles can be on either face of the PCB 40.

(22) The keying profile 48 also forms first and second current fingers 54a, 54b which extend from the perimeter 46 of the PCB 40 and are spaced from one another by a current spacing perimeter portion 56. In this way, the first current mating member 24 includes first and second current mating member portions 24a, 24b. The first current finger 54a defines a length L.sub.C1 of the first current mating member portion 24a, and the second current finger 54b defines a length L.sub.C2 of the second current mating member portion 24b.

(23) Each of the first and second current fingers 54a, 54b includes a first interference member portion 58a, 58b which extends from a respective current finger 54a, 54b.

(24) Each current finger 54a, 54b has separate current poles (not shown) which provide the current connection to the primary current transformer 14. One of the current poles is on one face of the PCB 40 while the other pole is on the opposite face of the PCB 40.

(25) The first voltage mating member 26 and first current mating member 24 are spaced from one another along the perimeter 46 of the PCB 40 by a member spacing perimeter portion 60.

(26) Further features of the protection relay connector 22 are now described in relation to FIG. 4. The protection relay connector 22 includes a voltage aperture 62 and a voltage mating member cover 64 that extends across the voltage aperture 62 so as to provide the second voltage mating member 38. The voltage mating member cover 64 is used together with metal contacts (not shown) housed within the voltage aperture 62 to create a connector voltage channel.

(27) More specifically, the voltage mating member cover 64 includes first and second voltage mating apertures (in the form of slots in the embodiment shown) 66a, 66b shaped to receive the first and second voltage fingers 50a, 50b. The first and second voltage mating slots 66a, 66b are in line with one another and are spaced from each other by a second interference member portion 68.

(28) The first and second voltage mating slots 66a, 66b and the interference member portion 68 define an overall length L.sub.V of the second voltage mating member 38 which is equal to the overall length L.sub.V of the first voltage mating member 26 (taking into account any tolerance stack-up). Moreover, the individual length of each of the first and second voltage mating slots 66a, 66b is equal to the individual length of each of the first and second voltage fingers 50a, 50b. As such, the first and second voltage fingers 50a, 50b are inserted into the first and second voltage mating slots 66a, 66b so as to mate the first voltage mating member 26 with the second voltage mating member 38.

(29) The protection relay connector 22 further includes first and second current apertures 70a, 70b and first and second current mating member covers 72a, 72b that each extend across a corresponding first and second current aperture 70a, 70b, thus defining first and second current mating member portions 36a, 36b. The current mating member covers 72a, 72b together with metal contacts (not shown) housed within the first and second current apertures 70a, 70b creates first and second connector current channels.

(30) More specifically, the first current mating member cover 72a includes a first current mating aperture (in the form of a single slot in this embodiment) 74a shaped to receive the first current finger 54a, and the second current mating member cover 72b includes a second current mating aperture (also in the form of a single slot) 74b shaped to receive the second current finger 54b.

(31) Each current mating slot 74a, 74b defines a length L.sub.C1, L.sub.C2 of a respective first and second current mating member portion 36a, 36b of the second current mating member 36, which is equal to the length L.sub.C1, L.sub.C2 of each of the first and second current fingers 54a, 54b (taking into account any tolerance stack-up).

(32) As such, the first and second current fingers 54a, 54b are inserted into a corresponding current mating slot 74a, 74b so as to mate the first current mating member 24 with the second current mating member 36.

(33) The overall length L.sub.V of the voltage fingers 50a, 50b of the PCB 40 is longer than the length L.sub.C1, L.sub.C2 of either of the current mating slots 74a, 74b of the protection relay connector 22. Therefore, the voltage fingers 50a, 50b will not fit in either of the current mating slots 74a, 74b, such that mating of the first voltage mating member 26 with the second current mating member 36 is prevented.

(34) Meanwhile, the first interference member portion 58a, 58b of either of the first and second current fingers 54a, 54b abuts the second interference member portion 68 of the second voltage mating member 38. Therefore, neither of the first and second current fingers 54a, 54b will fit into the voltage mating slots 66a, 66b, such that mating of the first current mating member 24 with the second voltage mating member 38 is prevented.

(35) In other embodiments of the invention (not shown), the first and second current and voltage mating members 24, 26, 36, 38 may take any other suitable shape which permits the mating of the first and second current mating members 24, 36 with one another and the first and second voltage mating members 26, 38 with another, while preventing mating of the first current mating member 24 with the second voltage mating member 38 and mating of the first voltage mating member 26 with the second current mating member 36.

(36) In such other embodiments, the shape of the first and second current and voltage mating members 24, 26, 36, 38 may be such that the second current and voltage mating members 36, 38 are inserted into the first current and voltage mating members 24, 26.

(37) In further embodiments of the invention (not shown), the protection relay connector 22 may instead include a single connector current channel (i.e. a single current aperture 70a, corresponding current mating member cover 72a and metal contact), and two connector voltage channels (i.e. two voltage apertures 62, corresponding voltage mating member covers 64 and metal contacts). In such an embodiment, the first current mating member 24 may be formed from a single current member portion 24a, i.e. a single current finger 54a with one current pole for connecting to the primary current transformer 14 being provided on one face of the protection relay data acquisition board 20, and the other current pole for connecting to the primary current transformer 14 being provided on the other opposite face of the protection relay data acquisition board 20.

(38) As shown in FIG. 4, the protection relay connector 22 includes three sets 76a, 76b, 76c of second current and voltage members 36, 38. Each set 76a, 76b, 76c may be connected to a different phase of the electrical network 12. Each set 76a, 76b, 76c may instead be connected at different locations of the same phase of the electrical network 12. In each case, separate PCBs 40 would be provided to mate with each set 76a, 76b, 76c of second current and voltage members 36, 38.

(39) In other embodiments of the invention (not shown), the first and second current mating members 24, 36 share a common current visual indicator and the first and second voltage mating members 26, 38 share a common voltage visual indicator. The current and voltage visual indicators are different from one another. For example, a colour coding could be used on both the protection relay data acquisition board 20 and the protection relay connector 22 to indicate whether a particular connection is configured for use with current or voltage transformer channels. The coding may also indicate the operating phase of the connection.

(40) In use, the current connections of the primary current transformer 14 are connected to the first and second current apertures 70a, 70b of the protection relay connector 22 via the metal contacts. Moreover, the voltage connections of the primary voltage transformer 16 are connected to the voltage apertures 62 of the protection relay connector 22 via the metal contacts.

(41) The protection relay data acquisition board 20 is mated to the protection relay connector 22 via respective current and voltage mating members 24, 26, 36, 38. In particular, the first voltage finger 50a of the PCB 40 is inserted into the first voltage mating slot 66a of the voltage mating member cover 64, and the second voltage finger 50b of the PCB 40 is inserted into the second voltage mating slot 66b of the voltage mating member cover 64. At the same time, the first current finger 54a is inserted into the first current mating slot 74a of the first current mating member cover 72a, and the second current finger 54b is inserted into the second current mating slot 74b of the second current mating member cover 72b.

(42) As such, the shunt 42 provided on the PCB 40 is connected to the current connections of the primary current transformer 14, while the voltage divider 44 provided on the PCB 40 is connected to the voltage connections of the primary voltage transformer 16.

(43) The protection relay 18 may be connected to a circuit breaker (not shown) which is in turn connected to the electrical network 12.

(44) If the PCB 40 is attempted to be inserted into the protection relay connector 22 upside down, the first interference member portion 58a of the first current finger 54a will abut the second interference member portion 68 of the voltage mating member cover 64. Moreover, the first and second voltage fingers 50a, 50b will abut the top edges of the first current mating slot 74a due to the overall length L.sub.V of the voltage fingers 50a, 50b being longer than the length L.sub.C1 of the first current mating slot 74a.

(45) Accordingly, the PCB 40 will be prevented from being inserted into the protection relay connector 22, and thus incorrect connection of the current and voltage channels to the primary current and voltage transformers 14, 16 is prevented.

(46) Once the PCB 40 has been inserted correctly, the primary current and voltage transformers 14, 16 feed measured current and voltage waveforms of the electrical network 12 to the shunt 42 and voltage divider 44 via the protection relay connector 22. The shunt 42 converts the measured current waveform into a representative current waveform and the voltage divider 44 converts the measured voltage waveform into a representative voltage waveform. The digital-to-analogue converter (not shown) on the PCB 40 then produces respective digital representations of the current and voltage waveforms for inputting to the protection relay 18.

(47) In this way, measured current and voltage waveforms of the electrical network 12 are transmitted to the protection relay 18.

(48) The protection relay 18 can then trigger the circuit breaker upon detection of a fault on the electrical network 12 based on the current and voltage measurements.