CN104092191A - Alternating-current bus differential protection method - Google Patents
Alternating-current bus differential protection method Download PDFInfo
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- CN104092191A CN104092191A CN201410289719.1A CN201410289719A CN104092191A CN 104092191 A CN104092191 A CN 104092191A CN 201410289719 A CN201410289719 A CN 201410289719A CN 104092191 A CN104092191 A CN 104092191A
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- bus differential
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- 238000000034 method Methods 0.000 title claims abstract description 20
- 230000005540 biological transmission Effects 0.000 abstract description 6
- 230000008878 coupling Effects 0.000 abstract 1
- 238000010168 coupling process Methods 0.000 abstract 1
- 238000005859 coupling reaction Methods 0.000 abstract 1
- 238000005259 measurement Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000000205 computational method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
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Abstract
The invention relates to an alternating-current bus differential protection method, and belongs to the technical field of flexible direct-current transmission. The alternating-current bus differential protection method is provided to aim at a topological structure and measurement point configuration of the topological structure, wherein the topological structure is grounded through resistance and obtained after an alternating-current bus on a coupling variable valve side is connected with a three-phase electric reactor in parallel. The method comprises the steps that voltages of all phases and the total grounded current of the valve side are firstly collected, and currents of all the phases of the grounded electric reactor are calculated according to the ground resistance and the actual parameters of the electric reactor; the absolute value of difference currents is calculated according to the collected currents of the phases of the valve side, the currents of all phases of a valve side of a starting circuit and the currents, obtained through calculation, of the phases of the grounded electric reactor; whether the difference value of the currents is larger than a protection fixed value or not is judged, and if the difference value of the currents is larger than the protection fixed value, alternating-current bus differential protection is started. The method can judge a fault fast and accurately, and the whole system is effectively protected.
Description
Technical field
The present invention relates to a kind of ac bus differential protecting method, belong to Technology of HVDC based Voltage Source Converter field.
Background technology
Connect that to become valve side ac bus region be the important component part of flexible DC power transmission system, ac bus differential protection is the main protection of this region internal fault, the defencive function in feasible region when ground connection or short trouble.Existing flexible DC power transmission Practical Project is little, and topological structure has larger difference, has no the detailed description of ac bus differential protection.
Summary of the invention
The object of this invention is to provide a kind of ac bus differential protecting method, connect to solve the differential protection problem becoming after valve side ac bus three-phase reactor in parallel through the topological structure of grounding through resistance.
The present invention provides a kind of ac bus differential protecting method for solving the problems of the technologies described above, and the method comprises the following steps:
1) the each phase voltage of converter valve side and the ground connection total current of collection ac bus differential protection measuring point used, according to each phase current of the actual parameter calculating earthing reactor of earth resistance and reactor;
2) collection connects the each phase current of change valve side and starts the each phase current of return valve side, and respectively differs the absolute value of stream according to the each phase current calculating ac bus district that calculates earthing reactor;
3) whether the absolute value that judges each phase differential current is greater than protection definite value, as long as there is an absolute value that differs stream to be greater than protection definite value, just starts ac bus differential protection.
Described step 1) in the computing formula of the each phase current of earthing reactor as follows:
Wherein I
l_A/B/Cfor the electric current of the each phase of earthing reactor, U
acD_A/B/Cfor the each phase voltage value of valve side gathering, R earth resistance actual parameter value, I
gNDfor the ground connection total current value gathering, ω is constant, L
a/B/Cfor reactor actual parameter value.
Described step 2) in respectively to differ the computing formula of absolute value of stream as follows ac bus district:
DIF
A/B/C＝|IVD
A/B/C-IVC
A/B/C-I
L_A/B/C|
Wherein DIF
a/B/Cfor respectively differing the absolute value of stream, IVD
a/B/Cfor the each phase current of valve side, IVC
a/B/Cfor starting the each phase current of return valve side, I
l_A/B/Cfor the each phase current of earthing reactor calculating.
Described step 3) in the criterion of differential protection be:
DIF
a/B/C> Δ, time delay T, sends block signal, starts differential protection, and Δ is protection definite value, and T is the action delay time.
The invention has the beneficial effects as follows: the present invention be directed to and connect a kind of ac bus differential protecting method proposing through topological structure and its measuring point arrangement of grounding through resistance after change valve side ac bus three-phase reactor in parallel, first the method gathers the each phase voltage of valve side and ground connection total current, then calculates the electric current of the each phase of earthing reactor according to the actual parameter of earth resistance and reactor; Calculate the absolute value of the stream of going on business according to the each phase current of the each phase current of valve side gathering and the earthing reactor that starts the each phase current of return valve side and calculate; Judge whether electric current difference is greater than protection definite value, if be greater than, start ac bus differential protection.The present invention is failure judgement fast and accurately, effectively protects whole system.
Brief description of the drawings
Fig. 1 is flexible DC power transmission system topology and ac bus district measuring point schematic diagram;
Fig. 2 is the logic diagram of each phase reactor current computational methods in the present invention;
Fig. 3 is the logic diagram of ac bus differential protecting method of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is further described.
What the present invention is directed to is topological structure and its measuring point arrangement through grounding through resistance after connection change valve side ac bus three-phase reactor in parallel, and flexible DC power transmission system topology and ac bus district measuring point are illustrated as shown in Figure 1.The region of ac bus differential protection is as the region of square frame in Fig. 1; Ac bus differential protection measuring point used is the each phase voltage value U of valve side
acD_A/B/C, earth resistance total current value I
gND, connect and become the each phase current IVD of valve side
a/B/C, start the each phase current IVC of return valve side
a/B/C.The implementation method of ac bus differential protection of the present invention comprises the following steps:
1. gathering ac bus differential protection measuring point used is the each phase voltage value U of valve side
acD_A/B/C, earth resistance total current value I
gND, calculate the each phase current I of earthing reactor
l_A/B/C:
2. gather to connect and become the each phase current IVD of valve side
a/B/C, start the each phase current IVC of return valve side
a/B/Cwith the each phase current I of the earthing reactor calculating in step 1
l_A/B/C, as shown in Figure 2, calculating ac bus district respectively differs the absolute value DIF of stream
a/B/C:
DIF
A/B/C＝|IVD
A/B/C-IVC
A/B/C-I
L_A/B/C|
3. whether the absolute value that judges each phase differential current is greater than protection definite value, as long as there is an absolute value that differs stream to be greater than protection definite value, just starts ac bus differential protection.
As shown in Figure 3, the protection criterion of ac bus differential protection is:
DIF
a/B/Cwhen > Δ, time delay T, sends block signal, starts ac bus differential protection, and wherein Δ is protection definite value, and T is the action delay time;
Ac bus differential protecting method of the present invention can adopt built-in industrial control platform or PC device to realize, and these two kinds of devices are high pressure, the conventional device of extra-high-speed direct current transportation and flexible DC power transmission field.First protective device gathers ac bus differential protection measuring point used is the each phase voltage value U of valve side
acD_A/B/C, earth resistance total current value I
gND, connect and become the each phase current IVD of valve side
a/B/C, start the each phase current IVC of return valve side
a/B/C, then carry out logic judgement and processing according to the logic diagram (as shown in Figures 2 and 3) of protection.
Claims (4)
1. an ac bus differential protecting method, is characterized in that, this guard method comprises the following steps:
1) the each phase voltage of converter valve side and the ground connection total current of collection ac bus differential protection measuring point used, according to each phase current of the actual parameter calculating earthing reactor of earth resistance and reactor;
2) collection connects the each phase current of change valve side and starts the each phase current of return valve side, and respectively differs the absolute value of stream according to the each phase current calculating ac bus district that calculates earthing reactor;
3) whether the absolute value that judges each phase differential current is greater than protection definite value, as long as there is an absolute value that differs stream to be greater than protection definite value, just starts ac bus differential protection.
2. a kind of ac bus differential protecting method according to claim 1, is characterized in that described step 1) in the computing formula of the each phase current of earthing reactor as follows:
Wherein I
l_A/B/Cfor the electric current of the each phase of earthing reactor, U
acD_A/B/Cfor the each phase voltage value of valve side gathering, R earth resistance actual parameter value, I
gNDfor the ground connection total current value gathering, ω is constant, L
a/B/Cfor reactor actual parameter value.
3. a kind of ac bus differential protecting method according to claim 2, is characterized in that described step 2) in respectively to differ the computing formula of absolute value of stream as follows ac bus district:
DIF
A/B/C＝|IVD
A/B/C-IVC
A/B/C-I
L_A/B/C|
Wherein DIF
a/B/Cfor respectively differing the absolute value of stream, IVD
a/B/Cfor the each phase current of valve side, IVC
a/B/Cfor starting the each phase current of return valve side, I
l_A/B/Cfor the each phase current of earthing reactor calculating.
4. a kind of ac bus differential protecting method according to claim 3, is characterized in that described step 3) in the criterion of differential protection be:
DIF
a/B/C> Δ, time delay T, sends block signal, starts differential protection, and Δ is protection definite value, and T is the action delay time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410289719.1A CN104092191B (en) | 2014-06-24 | A kind of ac bus differential protecting method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410289719.1A CN104092191B (en) | 2014-06-24 | A kind of ac bus differential protecting method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104092191A true CN104092191A (en) | 2014-10-08 |
| CN104092191B CN104092191B (en) | 2016-11-30 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105119249A (en) * | 2015-06-30 | 2015-12-02 | 许昌许继软件技术有限公司 | Bridge differential protection method of current conversion system |
| CN107453386A (en) * | 2017-08-24 | 2017-12-08 | 中国南方电网有限责任公司 | Power transmission control method and flexible DC power transmission device |
| CN115173379A (en) * | 2022-08-17 | 2022-10-11 | 国网经济技术研究院有限公司 | Symmetrical monopole flexible direct current grounding system and grounding parameter selection method thereof |
Citations (4)
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| EP2580828A1 (en) * | 2010-06-14 | 2013-04-17 | ABB Research Ltd. | Fault protection of hvdc transmission lines |
| CN103346541A (en) * | 2013-06-20 | 2013-10-09 | 国家电网公司 | Convertor station direct current filter differential protection method and device |
| CN103633620A (en) * | 2013-11-11 | 2014-03-12 | 中国南方电网有限责任公司超高压输电公司 | Novel configuration method for zero-sequence differential protection of converter transformer |
| CN103872657A (en) * | 2014-03-19 | 2014-06-18 | 许继集团有限公司 | Metal loop wire longitudinal differential protection method in parallel-connection ice melting mode |
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| EP2580828A1 (en) * | 2010-06-14 | 2013-04-17 | ABB Research Ltd. | Fault protection of hvdc transmission lines |
| CN103346541A (en) * | 2013-06-20 | 2013-10-09 | 国家电网公司 | Convertor station direct current filter differential protection method and device |
| CN103633620A (en) * | 2013-11-11 | 2014-03-12 | 中国南方电网有限责任公司超高压输电公司 | Novel configuration method for zero-sequence differential protection of converter transformer |
| CN103872657A (en) * | 2014-03-19 | 2014-06-18 | 许继集团有限公司 | Metal loop wire longitudinal differential protection method in parallel-connection ice melting mode |
Non-Patent Citations (2)
| Title |
|---|
| 吴晓红等: "220kV母线差动保护双位置继电器故障分析及解决", 《电力科学与工程》 * |
| 邓旭阳等: "交流二次回路中性线阻抗对母线差动保护的影响及防范措施", 《电力系统保护与控制》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105119249A (en) * | 2015-06-30 | 2015-12-02 | 许昌许继软件技术有限公司 | Bridge differential protection method of current conversion system |
| CN105119249B (en) * | 2015-06-30 | 2017-09-19 | 许昌许继软件技术有限公司 | A kind of bridge differential protecting method of commutation system |
| CN107453386A (en) * | 2017-08-24 | 2017-12-08 | 中国南方电网有限责任公司 | Power transmission control method and flexible DC power transmission device |
| CN115173379A (en) * | 2022-08-17 | 2022-10-11 | 国网经济技术研究院有限公司 | Symmetrical monopole flexible direct current grounding system and grounding parameter selection method thereof |
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