CT secondary through-flow method for power plant
阅读说明：本技术 一种发电厂ct二次通流方法 (CT secondary through-flow method for power plant ) 是由 王思聪 罗凯 张清 杜辉 袁鹏涛 刘武旭 邓桥 于 2021-08-05 设计创作，主要内容包括：本发明涉及一种发电厂CT二次通流方法,包括：串联各个CT的所有电流回路,在CT二次通流试验时,通过在某个就地端子箱的一处施加电流,检查所有CT二次回路接线的正确性及完整性；通过分别施加不同幅值、相序的电流,进一步检查CT二次回路的正确性,并同时检查发变组保护柜、故障录波柜、DCS后台采样及参数设置的正确性。本发明无需在各个CT端子处分别进行通流,提高了试验效率,实用性强,适用于不同电厂电气主系统。(The invention relates to a CT secondary through-flow method for a power plant, which comprises the following steps: all current loops of each CT are connected in series, and during a CT secondary through-current test, the correctness and the integrity of the wiring of all CT secondary loops are checked by applying current at one position of a certain local terminal box; the correctness of the CT secondary circuit is further checked by respectively applying currents with different amplitudes and phase sequences, and the correctness of the generator-transformer protection cabinet, the fault recording cabinet, the DCS background sampling and parameter setting is checked at the same time. The invention does not need to respectively carry out through-flow at each CT terminal, improves the test efficiency, has strong practicability and is suitable for electrical main systems of different power plants.)
1. A power plant CT secondary through-flow method is characterized by comprising the following steps:
all current loops of each CT are connected in series, and the wiring correctness and integrity of all CT secondary loops are checked by applying current at one position of a certain local terminal box during the CT secondary through-current test.
2. A power plant CT secondary through-flow method according to claim 1, characterized in that the method further comprises:
the correctness of the CT secondary circuit is further checked by respectively applying currents with different amplitudes and phase sequences, and the correctness of the generator-transformer protection cabinet, the fault recording cabinet, the DCS background sampling and parameter setting is checked at the same time.
3. The power plant CT secondary through-flow method of claim 2, wherein the on-site terminal box comprises a No. 1 CT body terminal box and a No. 2 CT body terminal box; a terminal a4011, a terminal B4011, a terminal C4011, a terminal N4011A, a terminal N4011B, a terminal N4011C, a terminal a4021, a terminal B4021, a terminal C4021, a terminal N4021A, a terminal N4021B, a terminal N4021C, a terminal a4031, a terminal B4031, a terminal C4031, a terminal N4031A, a terminal N4031B, a terminal N4031C, a terminal a4041, a terminal B4041, a terminal C4041, a terminal N4041A, a terminal N4041B, and a terminal N40 4041C are sequentially arranged in the No. 1 CT main body terminal box; the No. 2 CT main body terminal box is provided with a terminal a4051, a terminal B4051, a terminal C4051, a terminal N4051A, a terminal N4051B, a terminal N4051C, a terminal a4061, a terminal B4061, a terminal C4061, a terminal N4061A, a terminal N4061B, a terminal N4061C, a terminal a4071, a terminal B4071, a terminal C4071, a terminal N4071A, a terminal N4071B, a terminal N4071C, a terminal a4081, a terminal B4081, a terminal C4081, a terminal N40 4081A, a terminal N40 4081B, and a terminal N40 4081C in this order, and the specific flow-passing method is as follows:
1) all CT connecting pieces except a vertically long connecting piece among a terminal N4081A, a terminal N4081B and a terminal N4081C in the terminal box of the No. 2 CT body are disconnected, so that current is prevented from being induced by the primary side when the secondary side is in current flowing, and the independence of the phases of the currents is ensured;
2) a short-wiring connecting terminal N4011A, a terminal A4021, a terminal N4021A and a terminal A4031, a terminal N4031A and a terminal A4041 are sequentially arranged in a No. 1 CT body terminal box;
3) a short-wiring connecting terminal N4011B, a terminal B4021, a terminal N4021, a terminal B4031, a terminal N4021B and a terminal B4031, and a terminal N4031B and a terminal B4041 are sequentially arranged in a No. 1 CT body terminal box;
4) a short-wiring connecting terminal N4011C, a terminal C4021, a terminal N4021C, a terminal C4031, a terminal N4031C and a terminal C4041 are sequentially arranged in a No. 1 CT body terminal box;
5) connecting a terminal N4041A of a No. 1 CT main body terminal box and a terminal A4051 of a No. 2 CT main body terminal box by using a short-circuit wire;
6) connecting terminal N4041B of No. 1 CT main body terminal box and terminal B4051 of No. 2 CT main body terminal box by short-circuit wire;
7) connecting terminal N4041C of No. 1 CT main body terminal box and terminal C4051 of No. 2 CT main body terminal box by short-circuit wires;
8) in a No. 2 CT main body terminal box, a short-wiring connecting terminal N4051A, a terminal A4061, a terminal N4061A, a terminal A4071, a terminal N4071A and a terminal A4081 are used in sequence;
9) a short-wiring connecting terminal N4051B, a terminal B4061, a terminal N4061B, a terminal B4071, a terminal N4071B and a terminal B4081 are sequentially arranged in a No. 2 CT main body terminal box;
10) a short-wiring connecting terminal N4051C, a terminal C4061, a terminal N4061C, a terminal C4071, a terminal N4071C and a terminal C4081 are sequentially arranged in a No. 2 CT main body terminal box;
11) respectively connecting a current output terminal A, B, C of a relay protection tester to a terminal A4011, a terminal B4011 and a terminal C4011 of a No. 1 CT body terminal box, and connecting a current output terminal N of the relay protection tester to a terminal N4081A of a No. 2 CT body terminal box;
12) a, B, C three-phase currents with different amplitudes and phases are output by a relay protection instrument;
13) respectively reading and recording the current amplitude and phase through a generator-transformer unit protection cabinet, a fault recording cabinet and a DCS background, judging whether the amplitude and the phase are consistent with the output of a relay protection tester or not, and if so, entering the step 15); if the judgment result is negative, entering step 14);
14) closing the relay protection tester, searching and eliminating defects of a CT secondary circuit, a generator-transformer set protection cabinet, a fault recording cabinet and a DCS background, and returning to the step 13);
15) for the screen cabinet which can not read the current amplitude and the phase position flowing through the current loop, measuring whether the amplitude and the phase position are consistent with the output of the relay protection tester or not through a pincerlike ammeter, and if so, entering the step 17); if the judgment result is negative, entering the step 16);
16) closing the relay protection tester, searching and eliminating defects of the CT secondary circuit, and returning to the step 15);
17) adjusting the output current of the relay protection tester to A, B, C three-phase positive sequence rated current;
18) respectively reading and recording the current amplitude and phase through a generator-transformer unit protection cabinet, a fault recording cabinet and a DCS background, judging whether the amplitude and the phase are consistent with the output of a relay protection tester or not, and if so, entering a step 20); if the judgment result is negative, entering step 19);
19) closing the relay protection tester, searching and eliminating defects of a CT secondary circuit, a generator-transformer set protection cabinet, a fault recording cabinet and a DCS background, and returning to the step 18);
20) for the screen cabinet which can not read the current amplitude and the phase position flowing through the current loop, measuring whether the amplitude and the phase position are consistent with the output of the relay protection tester or not through a pincerlike ammeter, and if so, entering the step 22); if the judgment result is no, entering the step 21);
21) closing the relay protection tester, searching and eliminating defects of the CT secondary circuit, and returning to the step 20);
22) closing the relay protection tester, and disconnecting a current output line of the relay protection tester;
23) removing all the short wires added in the through-flow process;
24) all broken webs are restored.
Technical Field
The invention relates to the technical field of electric power tests, in particular to a CT secondary through-flow method for a power plant.
Background
Before a unit is put into operation or when the unit is overhauled, a power plant needs to check and confirm the wiring, the transformation ratio, the accuracy level, the polarity and the like of a CT (current transformer) in the whole plant, so that a CT body and a secondary circuit are correct, an open circuit phenomenon does not exist, otherwise the safe and stable operation of a power system is influenced, wherein the CT secondary through-flow is a necessary test item.
The current commonly used CT secondary through-flow method is carried out in a CT body terminal box, and tests are carried out by respectively carrying out secondary through-flow on each phase of each group of CT.
Disclosure of Invention
The invention aims to provide a CT secondary through-flow method for a power plant, which can complete the secondary through-flow of all CTs in the power plant at the same time only by a short-circuit wire, thereby greatly saving time and labor.
The invention provides a CT secondary through-flow method for a power plant, which comprises the following steps:
all current loops of each CT are connected in series, and the wiring correctness and integrity of all CT secondary loops are checked by applying current at one position of a certain local terminal box during the CT secondary through-current test.
Further, the method further comprises:
the correctness of the CT secondary circuit is further checked by respectively applying currents with different amplitudes and phase sequences, and the correctness of the generator-transformer protection cabinet, the fault recording cabinet, the DCS background sampling and parameter setting is checked at the same time.
Furthermore, the local terminal box comprises a No. 1 CT body terminal box and a No. 2 CT body terminal box; a terminal a4011, a terminal B4011, a terminal C4011, a terminal N4011A, a terminal N4011B, a terminal N4011C, a terminal a4021, a terminal B4021, a terminal C4021, a terminal N4021A, a terminal N4021B, a terminal N4021C, a terminal a4031, a terminal B4031, a terminal C4031, a terminal N4031A, a terminal N4031B, a terminal N4031C, a terminal a4041, a terminal B4041, a terminal C4041, a terminal N4041A, a terminal N4041B, and a terminal N40 4041C are sequentially arranged in the No. 1 CT main body terminal box; the No. 2 CT main body terminal box is provided with a terminal a4051, a terminal B4051, a terminal C4051, a terminal N4051A, a terminal N4051B, a terminal N4051C, a terminal a4061, a terminal B4061, a terminal C4061, a terminal N4061A, a terminal N4061B, a terminal N4061C, a terminal a4071, a terminal B4071, a terminal C4071, a terminal N4071A, a terminal N4071B, a terminal N4071C, a terminal a4081, a terminal B4081, a terminal C4081, a terminal N40 4081A, a terminal N40 4081B, and a terminal N40 4081C in this order, and the specific flow-passing method is as follows:
1) all CT connecting pieces except a vertically long connecting piece among a terminal N4081A, a terminal N4081B and a terminal N4081C in the terminal box of the No. 2 CT body are disconnected, so that current is prevented from being induced by the primary side when the secondary side is in current flowing, and the independence of the phases of the currents is ensured;
2) a short-wiring connecting terminal N4011A, a terminal A4021, a terminal N4021A and a terminal A4031, a terminal N4031A and a terminal A4041 are sequentially arranged in a No. 1 CT body terminal box;
3) a short-wiring connecting terminal N4011B, a terminal B4021, a terminal N4021, a terminal B4031, a terminal N4021B and a terminal B4031, and a terminal N4031B and a terminal B4041 are sequentially arranged in a No. 1 CT body terminal box;
4) a short-wiring connecting terminal N4011C, a terminal C4021, a terminal N4021C, a terminal C4031, a terminal N4031C and a terminal C4041 are sequentially arranged in a No. 1 CT body terminal box;
5) connecting a terminal N4041A of a No. 1 CT main body terminal box and a terminal A4051 of a No. 2 CT main body terminal box by using a short-circuit wire;
6) connecting terminal N4041B of No. 1 CT main body terminal box and terminal B4051 of No. 2 CT main body terminal box by short-circuit wire;
7) connecting terminal N4041C of No. 1 CT main body terminal box and terminal C4051 of No. 2 CT main body terminal box by short-circuit wires;
8) in a No. 2 CT main body terminal box, a short-wiring connecting terminal N4051A, a terminal A4061, a terminal N4061A, a terminal A4071, a terminal N4071A and a terminal A4081 are used in sequence;
9) a short-wiring connecting terminal N4051B, a terminal B4061, a terminal N4061B, a terminal B4071, a terminal N4071B and a terminal B4081 are sequentially arranged in a No. 2 CT main body terminal box;
10) a short-wiring connecting terminal N4051C, a terminal C4061, a terminal N4061C, a terminal C4071, a terminal N4071C and a terminal C4081 are sequentially arranged in a No. 2 CT main body terminal box;
11) respectively connecting a current output terminal A, B, C of a relay protection tester to a terminal A4011, a terminal B4011 and a terminal C4011 of a No. 1 CT body terminal box, and connecting a current output terminal N of the relay protection tester to a terminal N4081A of a No. 2 CT body terminal box;
12) a, B, C three-phase currents with different amplitudes and phases are output by a relay protection instrument;
13) respectively reading and recording the current amplitude and phase through a generator-transformer unit protection cabinet, a fault recording cabinet and a DCS background, judging whether the amplitude and the phase are consistent with the output of a relay protection tester or not, and if so, entering the step 15); if the judgment result is negative, entering step 14);
14) closing the relay protection tester, searching and eliminating defects of a CT secondary circuit, a generator-transformer set protection cabinet, a fault recording cabinet and a DCS background, and returning to the step 13);
15) for the screen cabinet which can not read the current amplitude and the phase position flowing through the current loop, measuring whether the amplitude and the phase position are consistent with the output of the relay protection tester or not through a pincerlike ammeter, and if so, entering the step 17); if the judgment result is negative, entering the step 16);
16) closing the relay protection tester, searching and eliminating defects of the CT secondary circuit, and returning to the step 15);
17) adjusting the output current of the relay protection tester to A, B, C three-phase positive sequence rated current;
18) respectively reading and recording the current amplitude and phase through a generator-transformer unit protection cabinet, a fault recording cabinet and a DCS background, judging whether the amplitude and the phase are consistent with the output of a relay protection tester or not, and if so, entering a step 20); if the judgment result is negative, entering step 19);
19) closing the relay protection tester, searching and eliminating defects of a CT secondary circuit, a generator-transformer set protection cabinet, a fault recording cabinet and a DCS background, and returning to the step 18);
20) for the screen cabinet which can not read the current amplitude and the phase position flowing through the current loop, measuring whether the amplitude and the phase position are consistent with the output of the relay protection tester or not through a pincerlike ammeter, and if so, entering the step 22); if the judgment result is no, entering the step 21);
21) closing the relay protection tester, searching and eliminating defects of the CT secondary circuit, and returning to the step 20);
22) closing the relay protection tester, and disconnecting a current output line of the relay protection tester;
23) removing all the short wires added in the through-flow process;
24) all broken webs are restored.
By means of the scheme, the power plant CT secondary through-flow method has the following technical effects:
1) according to the invention, all current loops of each CT are connected in series, so that the correctness and the integrity of all CT secondary loop wiring can be checked by applying current to one position of a certain local terminal box in a CT secondary through-current test. Through-flow does not need to be carried out at each CT terminal, and the test efficiency is improved.
2) The invention further checks the correctness of the CT secondary circuit by respectively applying currents with different amplitudes and phase sequences, and simultaneously checks the correctness of sampling and parameter setting of devices such as a generator-transformer protection cabinet, a fault recording cabinet, a DCS background and the like.
3) The invention has strong practicability and is suitable for electrical main systems of different power plants.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Drawings
Fig. 1 is a schematic diagram of a CT secondary through-flow method of a power plant according to an embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
The embodiment provides a power plant CT secondary through-flow method, which comprises the following steps:
all current loops of each CT are connected in series, and the wiring correctness and integrity of all CT secondary loops are checked by applying current at one position of a certain local terminal box during the CT secondary through-current test.
The correctness of the CT secondary circuit is further checked by respectively applying currents with different amplitudes and phase sequences, and the correctness of the generator-transformer protection cabinet, the fault recording cabinet, the DCS background sampling and parameter setting is checked at the same time.
Referring to fig. 1 (only showing the current output line and the short-circuit line added to the terminal of the relay protection tester, and the external CT loop line of the terminal row is not shown), in an embodiment, the specific current flowing method includes:
1) all CT connecting pieces except the vertical long connecting pieces among the three terminals of N4081A, N4081B and N4081C in the CT body terminal box are disconnected, so that current is prevented from being induced by the primary side when the secondary side is in current flowing, and the independence of the phases is ensured.
2) In the terminal box of No. 1 CT main body, N4011A and A4021, N4021A and A4031, N4031A and A4041 are connected by short wires in sequence.
3) In a No. 1 CT main body terminal box, N4011B and B4021, N4021B and B4031, and N4031B and B4041 are connected in sequence by short wires.
4) In a No. 1 CT main body terminal box, N4011C and C4021, N4021C and C4031, N4031C and C4041 are connected by short wires in sequence.
5) N4041A of the No. 1 CT main body terminal box and a4051 of the No. 2 CT main body terminal box are connected by a short wire.
6) N4041B of the No. 1 CT main body terminal box and B4051 of the No. 2 CT main body terminal box are connected by a short wire.
7) N4041C of the No. 1 CT main body terminal box and C4051 of the No. 2 CT main body terminal box are connected by a short wire.
8) N4051A and A4061, N4061A and A4071, N4071A and A4081 are connected in sequence by short wires in a No. 2 CT main body terminal box.
9) N4051B and B4061, N4061B and B4071, N4071B and B4081 are connected in sequence by short wires in a No. 2 CT main body terminal box.
10) N4051C and C4061, N4061C and C4071, N4071C and C4081 are connected in sequence by short wires in a No. 2 CT main body terminal box.
11) The current output terminal A, B, C of the relay protection tester is respectively connected to the A4011, B4011 and C4011 of the No. 1 CT body terminal box, and the current output terminal N of the relay protection tester is connected to the N4081A of the No. 2 CT body terminal box.
12) A, B, C three-phase currents with different amplitudes and phases (positive sequence, zero sequence and negative sequence) are output by a relay protection instrument.
13) Respectively reading and recording the current amplitude and phase through a generator-transformer unit protection cabinet, a fault recording cabinet, a DCS background and the like, judging whether the amplitude and the phase are consistent with the output of a relay protection tester, and if so, entering the step 15); and if the judgment result is negative, the step 14) is carried out.
14) And (5) closing the relay protection tester, searching and eliminating defects of a CT secondary circuit, a generator-transformer set protection cabinet, a fault recording cabinet, a DCS background and the like, and then returning to the step 13).
15) For the screen cabinet which can not read the current amplitude and the phase position flowing through the current loop, measuring whether the amplitude and the phase position are consistent with the output of the relay protection tester or not through a pincerlike ammeter, and if so, entering the step 17); and if the judgment result is negative, the step 16) is carried out.
16) And (5) closing the relay protection tester, searching and eliminating defects of the CT secondary circuit, and returning to the step 15).
17) And adjusting the output current of the relay protection tester to be A, B, C three-phase positive sequence rated current.
18) Respectively reading and recording the current amplitude and phase through a generator-transformer unit protection cabinet, a fault recording cabinet, a DCS background and the like, judging whether the amplitude and the phase are consistent with the output of a relay protection tester, and if so, entering a step 20); if the judgment result is no, the step 19) is entered.
19) And (4) closing the relay protection tester, searching and eliminating defects of a CT secondary circuit, a generator-transformer set protection cabinet, a fault recording cabinet, a DCS background and the like, and then returning to the step 18).
20) For the screen cabinet which can not read the current amplitude and the phase position flowing through the current loop, measuring whether the amplitude and the phase position are consistent with the output of the relay protection tester or not through a pincerlike ammeter, and if so, entering the step 22); if the judgment result is no, the step 21) is entered.
21) And (5) closing the relay protection tester, searching and eliminating defects of the CT secondary circuit, and returning to the step 20).
22) And closing the relay protection tester, and disconnecting the current output line of the relay protection tester.
23) And removing all the short wires added in the through-flow process.
24) All broken webs are restored.
The invention has the following technical effects:
1) according to the invention, all current loops of each CT are connected in series, so that the correctness and the integrity of all CT secondary loop wiring can be checked by applying current to one position of a certain local terminal box in a CT secondary through-current test. Through-flow does not need to be carried out at each CT terminal, and the test efficiency is improved.
2) The invention further checks the correctness of the CT secondary circuit by respectively applying currents with different amplitudes and phase sequences, and simultaneously checks the correctness of sampling and parameter setting of devices such as a generator-transformer protection cabinet, a fault recording cabinet, a DCS background and the like.
3) The invention has strong practicability and is suitable for electrical main systems of different power plants.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, it should be noted that, for those skilled in the art, many modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.