CN213602408U - Branch protection device for direct current system of transformer substation - Google Patents
Branch protection device for direct current system of transformer substation Download PDFInfo
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- CN213602408U CN213602408U CN202022695416.3U CN202022695416U CN213602408U CN 213602408 U CN213602408 U CN 213602408U CN 202022695416 U CN202022695416 U CN 202022695416U CN 213602408 U CN213602408 U CN 213602408U
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Abstract
The utility model discloses a branch road protection device for direct current system of transformer substation, branch road protection device establishes ties and presents out between the branch road at direct current generating line and direct current, branch road protection device includes single chip microcomputer control unit and passes through isolated DC/DC converter, static change over switch, hall current sensor, leakage current sensor and the warning display unit that signal line and single chip microcomputer control unit are connected respectively. The utility model discloses when detecting the leakage current, not only can discover the trouble and report to the police, but also can realize the isolation to trouble district and direct current generating line under the circumstances that does not cut off the power supply, solved the problem that traditional insulation monitoring device can only report to the police and can't protect; the utility model discloses branch circuit protection device when detecting the branch circuit and taking place short-circuit fault, realizes the quick disconnection of load through static switch, and the excision time is within 1 millisecond.
Description
Technical Field
The utility model relates to a branch road protection device for direct current system of transformer substation.
Background
In a substation, a dc system is often used to supply power to loads such as relay protection, control, signals, computer monitoring, and emergency lighting. In order to improve the power supply reliability of the dc system and ensure the safe operation of important dc devices, corresponding dc system protection devices are generally used. At present, common direct current protection equipment comprises current quick-break protection, insulation monitoring and the like. The current quick-break protection mostly adopts a breaker thermomagnetic tripping mode, but the short-circuit current protection value of the device is a fixed value and cannot be adjusted according to different connected loads; insulation monitoring can find faults and give an alarm, but follow-up processing is required manually, and if the processing is not timely, insulation reduction is possibly developed into grounding or short-circuit faults.
SUMMERY OF THE UTILITY MODEL
Utility model purpose: the utility model discloses only can discover electric leakage trouble and report to the police when adopting insulating supervision to carry out DC protection among the prior art, need the artificial poor problem of the treatment efficiency who carries out the subsequent processing existence, provide a branch road protection device for transformer substation's direct current system.
The technical scheme is as follows: a branch road protection device for direct current system of transformer substation, branch road protection device establishes ties and presents between branch road (load) at direct current generating line and direct current, branch road protection device includes singlechip control unit and passes through isolated form DC/DC converter, static change over switch, hall current sensor, leakage current sensor and the warning display unit that signal line and singlechip control unit are connected respectively.
The static selector switch comprises two paths of static switches connected in parallel for output, and the input of one path of static switch is directly connected with a direct-current bus; and the input of the other static switch is connected with the direct current bus through the isolated DC/DC converter.
The two paths of static switches which are output in parallel are a direct-connection branch static switch S1 and an isolation branch static switch S2, the static switch S1 and the static switch S2 are MOS (metal oxide semiconductor) tubes or IGBT (insulated gate bipolar transistor) modules, and driving signals of the static switch S1 and the static switch S2 are led from a PWM (pulse-width modulation) output pin of the single chip microcomputer control unit.
Wherein the isolated DC/DC converter comprises a filter capacitor C1、C2Power tube Q1、Q2、Q3、Q4And a transformer T; power tube Q1、Q4And power tube Q2、Q3Divided into two groups to be alternately conducted under the drive of PWM signals when Q is equal1、Q4When the group is switched on under the drive of PWM signal, the current passes through the switch tube Q1Transformer T homonymous terminal and switch tube Q4Forming a loop; when Q is2、Q3When the group is switched on under the drive of PWM signal, the current passes through the switch tube Q2Transformer T different name end and switch tube Q3Forming a loop; the above-mentionedThe isolated DC/DC converter also comprises a fast recovery diode D1、D2、D3、D4The direct current rectified by the full-bridge rectification circuit passes through a filter inductor L1And a filter capacitor C2And outputting after filtering.
The transformer T is an isolation type high-frequency transformer.
Has the advantages that: the utility model discloses when detecting the leakage current, not only can discover the trouble and report to the police, but also can realize the isolation to trouble district and direct current generating line under the circumstances of not cutting off the power supply through isolated form DC/DC converter, solved the problem that traditional insulation monitoring device can only report to the police and can't protect; when the branch circuit protection device detects the short circuit fault of the branch circuit, the load is cut off through the static switch; finally, all be equipped with on every branch road the utility model discloses branch road protection device to can realize the direct positioning of trouble branch road, shorten the investigation time.
Drawings
Fig. 1 is a schematic diagram of the branch protection device of the present invention connected in series between a dc bus and a load;
fig. 2 is a schematic circuit diagram of the branch protection device of the present invention;
FIG. 3 is a schematic circuit diagram of an isolated DC/DC converter;
fig. 4 is a flowchart illustrating the operation of the bypass protection device.
Detailed Description
The technical solution of the present invention will be further explained with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the utility model is used for transformer substation's direct current system's branch protection device, branch protection device establish ties and present out between the branch road at direct current generating line and direct current, realize accurate "one-to-one" protection to the important load on the branch road to but the direct positioning shortens the investigation time to the branch road that breaks down.
As shown in fig. 2, DC0-5V signals of the hall current sensor and the insulation monitoring leakage current sensor are respectively connected to a single chip analog quantity acquisition pin of the single chip control unit through signal lines; the static switch adopts MOS tubes or IGBTs of S1 and S2 as switching elements, and a driving signal is led from a PWM output pin of the singlechip control unit; two outputs of the static switch are connected in parallel, and two inputs of the static switch are respectively that the static switch S1 is directly connected with the direct current bus and the static switch S2 is connected with the direct current bus through the isolated DC/DC converter.
As shown in FIG. 3, the DC/DC isolated converter adopts a full-bridge topology, UinIs an input voltage, UoTo output a voltage, L1Is a filter inductor, T is a high-frequency transformer, C1、C2For filtering capacitors, power tubes Q1、Q2、Q3、Q4Selecting IGBT module and rectifier diode D1、D2、D3、D4A fast recovery diode is selected. Wherein the high frequency transformer acts as an electrical isolation.
The working principle of the isolated DC/DC converter is as follows: c1For input filter capacitors, Q1、Q4And Q2、Q3Alternately conducted under the drive of PWM signals in two groups when Q is equal1、Q4When the group is switched on under the drive of PWM signal, the current passes through the switch tube Q1Transformer T homonymous terminal and switch tube Q4Forming a loop; when Q is2、Q3When the group is switched on under the drive of PWM signal, the current passes through the switch tube Q2Transformer T different name end and switch tube Q3Forming a loop; two groups are alternatively conducted to generate positive and negative alternative rectangular pulse waveforms, and the rectangular pulse waveforms are coupled to the secondary side through the primary side of a transformer T and then are coupled through a D1、D2、D3、D4The formed full-bridge rectifying circuit is rectified into direct current output which is output through L1And C2Filtering output DC voltage Uo。
As shown in fig. 4, when the protection device works, the single chip microcomputer control unit drives the direct-connection branch static switch S1 to be turned on, and turns off the isolation branch static switch S2; the Hall current sensor monitors the current change of the branch circuit in real time, when the current rising rate is too fast or the current value is larger, the short-circuit fault is judged, and the singlechip control unit closes the direct-connected branch circuit static switch S1 and gives an alarm through the alarm display unit; when no short-circuit fault exists, whether a leakage fault exists is monitored, whether the leakage current fault exists in the corresponding branch is monitored by the leakage current sensor in real time, when the leakage fault exists, the leakage current sensor sends a leakage signal to the single chip microcomputer control unit, the single chip microcomputer control unit alarms through the alarm display unit, the alarm display unit alarms and displays the magnitude of the leakage current and starts to time the leakage current, the timing time is set, when the set timing time is reached and the leakage current still exists, the single chip microcomputer control unit drives the isolation branch static switch S2 to be turned on, the direct-connected branch static switch S1 is turned off, the direct-current bus supplies power to a load through the isolation type DC/DC converter, the leakage fault is limited in the branch under the condition of no power failure, and the isolation operation of the branch and the direct-current.
Claims (5)
1. The utility model provides a branch road protection device for direct current system of transformer substation which characterized in that: the branch protection device is connected between the direct current bus and the direct current feed-out branch in series and comprises a single chip microcomputer control unit, and an isolated DC/DC converter, a static selector switch, a Hall current sensor, a leakage current sensor and an alarm display unit which are connected with the single chip microcomputer control unit through signal lines respectively.
2. The branch protection device for a substation dc system according to claim 1, characterized in that: the static selector switch comprises two paths of static switches connected in parallel for output, and the input of one path of static switch is directly connected with the direct-current bus; and the input of the other static switch is connected with the direct current bus through the isolated DC/DC converter.
3. The branch protection device for a substation dc system according to claim 2, characterized in that: the two paths of static switches which are output in parallel are a direct-connection branch static switch S1 and an isolation branch static switch S2, the static switch S1 and the static switch S2 are MOS (metal oxide semiconductor) tubes or IGBT (insulated gate bipolar transistor) modules, and driving signals of the static switch S1 and the static switch S2 are led from a PWM (pulse-width modulation) output pin of the single chip microcomputer control unit.
4. The branch protection device for a substation dc system according to claim 1, characterized in that: the isolated DC/DC converter comprises a filter capacitor C1、C2Power tube Q1、Q2、Q3、Q4And a transformer T; power tube Q1、Q4And power tube Q2、Q3Divided into two groups to be alternately conducted under the drive of PWM signals when Q is equal1、Q4When the group is switched on under the drive of PWM signal, the current passes through the switch tube Q1Transformer T homonymous terminal and switch tube Q4Forming a loop; when Q is2、Q3When the group is switched on under the drive of PWM signal, the current passes through the switch tube Q2Transformer T different name end and switch tube Q3Forming a loop; the isolated DC/DC converter also comprises a fast recovery diode D1、D2、D3、D4The direct current rectified by the full-bridge rectification circuit passes through a filter inductor L1And a filter capacitor C2And outputting after filtering.
5. The branch protection device for a substation dc system according to claim 4, characterized in that: the transformer T is an isolation type high-frequency transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022695416.3U CN213602408U (en) | 2020-11-19 | 2020-11-19 | Branch protection device for direct current system of transformer substation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022695416.3U CN213602408U (en) | 2020-11-19 | 2020-11-19 | Branch protection device for direct current system of transformer substation |
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| Publication Number | Publication Date |
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| CN213602408U true CN213602408U (en) | 2021-07-02 |
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| CN202022695416.3U Active CN213602408U (en) | 2020-11-19 | 2020-11-19 | Branch protection device for direct current system of transformer substation |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112564061A (en) * | 2020-11-19 | 2021-03-26 | 国网江苏省电力有限公司南通市海门区供电分公司 | Branch protection device for direct current system of transformer substation and protection method thereof |
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2020
- 2020-11-19 CN CN202022695416.3U patent/CN213602408U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112564061A (en) * | 2020-11-19 | 2021-03-26 | 国网江苏省电力有限公司南通市海门区供电分公司 | Branch protection device for direct current system of transformer substation and protection method thereof |
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