CN111009876A - Relay protection device and method for realizing rapid export of relay protection device - Google Patents
Relay protection device and method for realizing rapid export of relay protection device Download PDFInfo
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- CN111009876A CN111009876A CN201911423969.9A CN201911423969A CN111009876A CN 111009876 A CN111009876 A CN 111009876A CN 201911423969 A CN201911423969 A CN 201911423969A CN 111009876 A CN111009876 A CN 111009876A
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- relay
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- protection device
- relay protection
- mosfet
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- 238000000034 method Methods 0.000 title claims abstract description 15
- 230000001960 triggered effect Effects 0.000 claims abstract description 11
- 230000003111 delayed effect Effects 0.000 claims abstract description 3
- 238000005070 sampling Methods 0.000 claims description 8
- 230000002265 prevention Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000005669 field effect Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 125000006239 protecting group Chemical group 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/027—Details with automatic disconnection after a predetermined time
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- Emergency Protection Circuit Devices (AREA)
Abstract
The invention provides a relay protection device and a method for realizing quick export of the relay protection device, wherein a MOSFET is connected in series between two output contacts of a relay and is used as an export of the relay protection device; when the sudden change of the current is detected, the relay is immediately triggered to act, the current Fourier fundamental wave value is calculated after a half period of time delay, and when the current fundamental wave value is larger than the set action value, the MOSFET is controlled to be conducted, so that the relay protection device is quickly exported; the signal of the sudden change triggering relay action is automatically released after being kept for 500 ms; when the current fundamental wave value is smaller than the set action value after the fault is removed, the MOSFET is controlled to be disconnected in a delayed mode for 100ms, and the secondary circuit is guaranteed to be disconnected and arc is drawn by an auxiliary contact of the circuit breaker. The invention realizes the rapid export of the relay protection device by a simple and practical method, has important significance for early fault removal and accident enlargement prevention, and has convenient realization, reliable control and strong practicability.
Description
Technical Field
The invention relates to the technical field of relay protection, in particular to a relay protection device and a method for realizing quick export of the relay protection device.
Background
When a power system has a fault, the fault needs to be removed as soon as possible to avoid the expansion of the accident, which requires that the relay protection device installed can rapidly remove the fault. At present, relay contacts are mostly adopted in outlets of relay protection devices to trigger secondary tripping loops, the outlets of relays have the characteristics of high voltage resistance and strong anti-interference capability, but the action has time delay, the time delay from the action of triggering the relays to the closing of the contacts generally ranges from 4 ms to 8ms, and the maximum time delay generally does not exceed 10 ms. For the alternating current of 50Hz, the accurate protecting group wave value is calculated, and half period sampling data is generally needed, namely a time window of 10ms is needed, so that the actual outlet time of the relay protection device is more than 15 ms. Chinese patent 201610013025.4 gives a solution using IGBTs instead of relays, but this solution requires complex anti-interference hardware loops for IGBTs. The Chinese patent [201510126530.5] designs an intelligent switch controller with a fast outlet loop, and the scheme is mainly used for reducing transient voltage and inrush current during switching on; in addition, the scheme is a single device and needs to be controlled by a CPU, an FPGA, a CPLD and the like, so that the cost is high and the circuit is complex.
Disclosure of Invention
The invention provides a relay protection device and a method for realizing quick export of the relay protection device in order to solve the problems in the prior art, the quick export of the relay protection device is realized by a simple and practical method, and the method has important significance for early fault removal and accident enlargement prevention.
The invention provides a relay protection device, which comprises a relay for providing a relay control signal through a CPU, wherein an MOSFET is connected between two output contacts of the relay in series, and the MOSFET is connected with the CPU through the control signal. The relay is a loose relay DSP2a-DC24V, and the MOSFET is AOD468 of AOS.
The invention also provides a method for realizing the quick exit of the relay protection device, wherein an MOSFET (metal-oxide semiconductor field effect transistor) is connected in series between two output contacts of the relay and is used as the exit of the relay protection device; when the sudden change of the current is detected, the relay is triggered to act immediately, the calculation of the current Fourier fundamental wave value is started after 10ms delay, when the current fundamental wave value is larger than the set action value, the MOSFET is triggered to conduct a secondary trip circuit, the high-voltage circuit breaker is driven to act to remove the fault, and the relay protection device is enabled to be rapidly exported; the signal of the sudden change triggering relay action is automatically released after being kept for 500 ms; and when the current fundamental wave value is smaller than the set action value after the fault is removed, delaying 100ms to control the MOSFET to be switched off.
In a further improvement, the current is phase current, zero sequence current or differential current.
Further improved, when the current phase-taking current, namely continuous 3 sampling points satisfy | i φ (T) -2 x i φ (T-T) + i φ (T-2T) | >0.2In, a relay closing control signal is output, wherein: phi is A, B, C phase, In is rated current, i phi (T), i phi (T-T) and i phi (T-2T) are current sampling values at T moment, T-T moment and T-2T moment respectively, and T is current period.
Further, in order to ensure that the fault which does not meet the phase current sudden change amount can be reliably cut off, when the current fundamental wave value is larger than the set action value, the MOSFET is triggered to be conducted, and meanwhile the relay is triggered to act.
The invention has the beneficial effects that: the method is simple and practical, realizes the quick export of the relay protection device, has important significance for early fault removal and accident enlargement prevention, and is convenient to realize, reliable to control and strong in practicability.
Drawings
Fig. 1 is a schematic diagram of the operation of an embodiment of the present invention.
FIG. 2 is an exit timing diagram of an embodiment of the present invention.
Detailed Description
The invention will be further explained with reference to the drawings.
As shown in fig. 1, which is a working principle diagram of the present invention, a MOSFET is connected in series between two contacts of an outlet relay of a relay protection device, the outlet relay of the relay protection device is a loose relay DSP2a-DC24V, the relay is a single coil and controls the two contacts to operate simultaneously, the MOSFET is AOD468 of AOS, the MOSFET is connected between the two contacts of the relay and is not directly output to the outside, and the voltage withstand level and the anti-interference capability of the outlet of the relay protection device are irrelevant to the selected relay and the MOSFET. The relay protection device samples 32 points of each cycle of the analog quantity, namely the sampling interruption time is 0.625ms, whether the phase current has sudden change or not is judged in real time in the sampling interruption, and the judgment condition of the sudden change of the phase current is as follows:
| iφ(t)-2* iφ(t-T)+iφ(t-2T) |>0.2In；
wherein: phi is A, B, C three phases, In is rated current, i phi (T), i phi (T-T) and i phi (T-2T) are current sampling values at T moment, T-T moment and T-2T moment respectively, and T is a current period.
When any phase current continuously meets the criterion for 3 times, the condition that the phase current has sudden change is judged, the relay is triggered to act after the sudden change is judged, and the relay is automatically extended for 500 ms. And judging that the Fourier fundamental wave value of the three-phase current is calculated after 10ms of delay after the sudden change (the calculation of the Fourier fundamental wave value by half-wave is the prior art, and is not repeated herein), and controlling the conduction of the MOSFET (metal-oxide-semiconductor field effect transistor) when the fundamental wave value of any phase current is greater than the set action value, so that the outlet of the relay protection device acts, the secondary trip circuit is driven, and the high-voltage circuit breaker is tripped to remove the fault. After the fault is removed, when all phase current fundamental wave values are smaller than the set action value, the MOSFET is disconnected after being delayed for 100ms, and the secondary circuit is ensured to be disconnected and arc is drawn by an auxiliary contact of the circuit breaker. In order to ensure that the fault which does not meet the phase current surge amount is reliably removed, when the fundamental wave value of any phase current is larger than the set action value, the MOSFET is triggered to be conducted, and meanwhile, the relay is triggered to act.
As shown in fig. 2, it is an exit timing chart after the relay protection device of the present invention detects a fault, and the flow is as follows:
when a fault occurs in a power system at the time t0 (time 0 ms), the relay protection device judges that a current sudden change exists at the time t1 (time 1.875 ms), a relay action signal is output, a relay contact is closed at the time t2 (time 7.2 ms), the Fourier fundamental wave value of the current is calculated to be larger than the set action value at the time t3 (time 11.875 ms), a MOSFET (metal oxide semiconductor field effect transistor) conduction control signal is output, the MOSFET is instantaneously (with the delay of nanosecond and neglected), the outlet of the relay protection device is closed, and the total time from the fault to the outlet is 11.875ms, so that the purpose of rapidly outputting the relay protection device is achieved. After the relay protection device is exported, the MOSFET is turned off at the time t4 (the time 160.5 ms), an opening relay signal is output at the time t5 (the time 501.875 ms), the relay contact is opened at the time t6 (the time 504.9 ms), and the fault removal process is finished.
While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (6)
1. A relay protection device includes a relay for providing a relay control signal through a CPU, characterized in that: and an MOSFET is connected in series between two output contacts of the relay and is connected with the CPU through a control signal.
2. The relay protection device according to claim 1, wherein: the relay is a loose relay DSP2a-DC24V, and the MOSFET is AOD468 of AOS.
3. A method for realizing rapid exit of a relay protection device is characterized by comprising the following steps: a MOSFET is connected in series between two output contacts of the relay to serve as an outlet of the relay protection device; when the sudden change of the current is detected, the relay is immediately triggered to act, the current Fourier fundamental wave value is calculated after a half period of time delay, and when the current fundamental wave value is larger than the set action value, the MOSFET is controlled to be conducted, so that the relay protection device is quickly exported; the signal of the sudden change triggering relay action is automatically released after being kept for 500 ms; when the current fundamental wave value is smaller than the set action value after the fault is removed, the MOSFET is controlled to be disconnected in a delayed mode for 100ms, and the secondary circuit is guaranteed to be disconnected and arc is drawn by an auxiliary contact of the circuit breaker.
4. The method for realizing the rapid exit of the relay protection device according to claim 1, wherein: the current is phase current, zero sequence current or differential current.
5. The method for realizing the rapid exit of the relay protection device according to claim 1, wherein: when the current phase-taking current, namely continuous 3 sampling points meet the condition that | i phi (T) -2 x i phi (T-T) + i phi (T-2T) | >0.2In, a relay closing control signal is output, wherein: phi is A, B, C phase, In is rated current, i phi (T), i phi (T-T) and i phi (T-2T) are current sampling values at T moment, T-T moment and T-2T moment respectively, and T is current period.
6. The method for realizing the rapid exit of the relay protection device according to claim 1, wherein: in order to ensure that faults which do not meet the phase current surge amount can be reliably removed, when the current fundamental wave value is larger than the set action value, the MOSFET is triggered to be conducted, and meanwhile, the relay is triggered to act.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911423969.9A CN111009876A (en) | 2019-12-31 | 2019-12-31 | Relay protection device and method for realizing rapid export of relay protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911423969.9A CN111009876A (en) | 2019-12-31 | 2019-12-31 | Relay protection device and method for realizing rapid export of relay protection device |
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| Publication Number | Publication Date |
|---|---|
| CN111009876A true CN111009876A (en) | 2020-04-14 |
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| CN201911423969.9A Withdrawn CN111009876A (en) | 2019-12-31 | 2019-12-31 | Relay protection device and method for realizing rapid export of relay protection device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115207888A (en) * | 2022-09-15 | 2022-10-18 | 石家庄科林电气股份有限公司 | Rapid export method and device of relay protection device, terminal and storage medium |
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2019
- 2019-12-31 CN CN201911423969.9A patent/CN111009876A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115207888A (en) * | 2022-09-15 | 2022-10-18 | 石家庄科林电气股份有限公司 | Rapid export method and device of relay protection device, terminal and storage medium |
| CN115207888B (en) * | 2022-09-15 | 2022-12-06 | 石家庄科林电气股份有限公司 | Rapid export method and device of relay protection device, terminal and storage medium |
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Application publication date: 20200414 |