CN111740383B - Method for eliminating inrush current influence in coordinated control of generator set - Google Patents
Method for eliminating inrush current influence in coordinated control of generator set Download PDFInfo
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- CN111740383B CN111740383B CN202010608316.4A CN202010608316A CN111740383B CN 111740383 B CN111740383 B CN 111740383B CN 202010608316 A CN202010608316 A CN 202010608316A CN 111740383 B CN111740383 B CN 111740383B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/06—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
Abstract
The invention belongs to the field of electrical equipment and electrical engineering, and relates to the field of a generator set, in particular to a method for eliminating inrush current influence in coordinated control of the generator set, wherein when an operating transformer generates inrush current and meets the conditions that TA current exceeds the limit, the content of second harmonic of the TA current exceeds the limit, the negative sequence current of the TA current exceeds the limit, abnormal TV switching conditions and sudden TA current variable exceeding the limit switching conditions, the device starts to measure the TA and switches the TA to protection, so that the stability of coordinated control of the generator set is maintained, and the problem that the generator set trips because of power oscillation and serious time is avoided; the problem of when transformer air-drop or the electric wire netting takes place transient fault, the inrush current that the transformer in operation produced can lead to the measuring level current transformer that generator power transmitter used to take place saturation, makes its output can not the correct transmission become primary actual power, if the deviation is great and can take place to fluctuate by a wide margin to cause generating set coordinated control unstable, the unit power vibrates, can lead to the unit to trip when serious is solved.
Description
Technical Field
The invention belongs to electrical equipment and electrical engineering, relates to the field of generator sets, and particularly relates to a method for eliminating inrush current influence in coordinated control of a generator set, which is used for keeping the generator set coordinated and stable.
Background
When a transformer is dropped or a power grid has an instantaneous fault, a running transformer generates excitation inrush current and sympathetic inrush current, the inrush current contains obvious harmonic components and direct-current components, a measuring-level current transformer for a power transmitter of a generator is saturated, the output of the measuring-level current transformer cannot correctly transmit primary actual power, the deviation is large, large fluctuation can occur, unstable coordination control of a generator set can be caused, the power of the generator set vibrates, and the unit can be tripped seriously. The reason is that the traditional power transmitter collects the secondary voltage of a voltage transformer and the secondary current of a current transformer, realizes the multiplication operation of a power supply and the current through a time division multiplier, outputs the product of the current and the instantaneous value of the voltage, integrates the product of the current and the instantaneous value of the voltage, and outputs the product into an analog quantity to a corresponding measurement and control loop. The time division multiplier is a relatively common analog multiplication circuit, and its principle is that voltage and current signals are converted into alternating voltage signals by means of mutual inductor, and the two multiplied voltage input quantities are divided by a certain time delta t. Since Δ t is small, it can be considered that the input voltage can be regarded as alternating current or direct current within this Δ t. The multiplier multiplies the measured AC and DC values once at each time delta t, and then takes the average value in a given time (the time constant of the filter), namely the average value of the pulse area, namely the active power value, so as to realize the conversion that the DC average value is proportional to the product of the two measured AC and DC values. This algorithm is one that has been used in analog power transmitters. In the multiplier, a power frequency voltage curve to be measured and a 1000Hz high-frequency triangular line generate rectangular pulses through a mutual comparator, and the pulse width represents a voltage amplitude at a certain moment. It can be seen that the minimum clock pulse width of the power frequency voltage is minimum, the maximum clock pulse width of the power frequency voltage is maximum, and one power frequency voltage wave pattern is divided into 20 pulse waves; the output pulse width is used for cutting and separating the corresponding current waveform in the pulse width, and the area obtained by integrating the RC circuit is the power to be measured, and the power is sent to a control system to participate in the adjustment and control of the unit power.
The principle that combines power transmitter, when receiving the influence of an inrush current, the voltage pulse width who cuts apart in the multiplier during changer can not receive the influence, but the current amplitude in the voltage pulse width is very big, and lead to a large amount of harmonic power to produce during the inrush current, above reason leads to power constantly to increase in the voltage pulse width, the analog quantity that power transmitter produced also can quick increase, and then leads to the amplitude grow of power area in the big place of fluctuation, although generating set's real-time fundamental wave power is not big. In addition, the working principle and the response time of about 250ms of the traditional power transmitter at present do not have problems when measuring steady-state power, when inrush current is generated due to transformer air drop, power grid fault or sudden power change, the output of the power transmitter may be distorted due to the influence of response capability, and the distortion direction and magnitude of the output value of the power transmitter are related to the fault phase and moment, and are also related to factors such as the wiring mode of the power transmitter, the quality and the characteristic of the transmitter.
Disclosure of Invention
The invention aims to: the problem of when transformer air-drop or the electric wire netting takes place transient fault, the inrush current that the transformer in operation produced can lead to measuring level current transformer that generator power transmitter used to take place saturation, makes its output can not be accurate transmit and become primary actual power, if the deviation is great and can take place to fluctuate by a wide margin to cause generating set coordinated control unstable, the unit power vibrates, can lead to the unit to trip when serious is solved.
The technical scheme adopted by the invention is as follows:
a method for eliminating inrush current influence in coordinated control of a generator set comprises the steps of identifying logic judgment of possible inrush current time and fault time, wherein the logic judgment comprises switching conditions and alarm functions, the switching conditions comprise TA current out-of-limit, TA current second harmonic content out-of-limit, TA current negative sequence current out-of-limit and TA current mutation out-of-limit, and the alarm functions comprise TV disconnection alarm, TV abnormal alarm, TA disconnection alarm, TA measurement and TA protection difference current out-of-limit alarm.
Further, the TA current out-of-limit switching condition includes: when I is max ＞1.1I e When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA; corresponding alarm exit and alarm indicator light actions are simultaneously stored in the event record, wherein I max Is the maximum current, I e Rated current; and simultaneously starting a wave recording function.
Further, the TA current second harmonic content out-of-limit switching condition includes: when I max_2h ＞0.05I m &I m ＞0.2I e When the device starts to measure the TA and switches to the protection TA, the active power output of the device should be the active power calculated by the protection TA, wherein I max_2h Is the maximum second harmonic current, I m For measuring the level transformer current, I e Is a rated current; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; and simultaneously starting a wave recording function.
Further, the negative-sequence current switching condition of the TA current includes: when I 2m ＞0.06I e When the device starts to measure the TA and switches to the protection TA, the active power output of the device should be the active power calculated by the protection TA, wherein I 2m Measuring the negative sequence current of the transformer; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; and simultaneously starting a wave recording function.
Further, the TA current transient out-of-limit switching condition includes: when I is max(n) -I max(n-1) ＞0.2I e When the device starts to measure the TA and switches to the protection TA, the active power output of the device should be the active power calculated by the protection TA, wherein I max(n) Is a current at time n, I max(n-1) Is the current at time n-1, I e Rated current; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; and simultaneously starting a wave recording function.
Further, the TV disconnection warning includes: when U is formed 1 (Positive sequence voltage) < 20V&I max ＞5％I e Or U 1 (negative sequence voltage) > 2.5V, the device reports TV disconnection, and then the corresponding TV disconnection outlet and indicator lamp are actuated and simultaneously stored in the event record, wherein I max Is the maximum current, I e The rated current.
Further, the TV abnormal alarm includes: when TV1U 1 -TV2 U 1 > 2.5V or TV1U 1.max -TV2U 1.max When the voltage is more than 2.5V, the device reports TV abnormity, then corresponding alarm outlet and indicator lamp act, TV switching is started simultaneously, and the TV switching is stored in event record, wherein TV1U 1 For the positive sequence voltage of the first group of transformers, TV 2U 1 Positive sequence voltage of second group mutual inductor, TV1U 1.max Maximum positive sequence voltage, TV 2U, of the first group of transformers 1.max The maximum positive sequence voltage of the second group of mutual inductors.
Further, the TA disconnection warning includes: when 3I 0 ＞25％I max +5％I e &When the three-phase four-wire system is adopted, the device reports TA wire break, and then, the corresponding TA wire break outlet and the indicator lamp act and are simultaneously stored in an event record, wherein I 0 Is a zero sequence current, I max Maximum current, I e The rated current.
Further, the measuring TA and protection TA differential flow out-of-limit alarm includes: when I is max –I m.max ＞5％I m.max &I m.max ＞30％I e When the device reports the out-of-limit alarm of the difference flow between the measured TA and the protected TA, then, the corresponding alarm outlet and the indicator lamp act and are simultaneously stored in the event record, wherein, I max Is the maximum current, I m.max Maximum measurement of mutual inductor current, I e Is the rated current.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. in the invention, when the running transformer generates inrush current and meets the TA current out-of-limit, the second harmonic content of the TA current out-of-limit, the negative sequence current of the TA current out-of-limit, the TV abnormal switching condition and the TA current abrupt change out-of-limit switching condition, the device starts to measure the TA and switches the TA to the protection TA, thereby maintaining the stability of the coordinated control of the generator set and avoiding the problem that the generator set trips due to the power oscillation of the generator set and serious condition; and when the condition of the alarm function is met, the corresponding TV disconnection outlet and the corresponding indicator lamp can act, and the corresponding alarm outlet and the corresponding indicator lamp can act.
2. In the invention, when the running transformer generates inrush current and meets the switching conditions of TA current out-of-limit, TA current second harmonic content out-of-limit, TA current negative sequence current out-of-limit and TA current mutation out-of-limit, the device starts to measure TA and switches to protect TA so that the output power of the device is not lost, and the device also provides wave recording and alarm signals under the condition of ensuring that the power value is not lost, thereby being convenient for operators to find faults in time and solving the problems.
3. In the invention, the wave recording function in the logic judgment can automatically and accurately record the change conditions of various electrical quantities in the processes before and after the fault when the system has the fault, and has important functions of analyzing and processing the fault, judging whether the protection acts correctly or not and improving the safe operation level of the power system through the analysis and comparison of the electrical quantities.
Drawings
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Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
A method for eliminating inrush current influence in coordinated control of a generator set comprises the steps of identifying logic judgment of possible inrush current time and fault time, wherein the logic judgment comprises switching conditions and alarm functions, the switching conditions comprise TA current out-of-limit, TA current second harmonic content out-of-limit, TA current negative sequence current out-of-limit and TA current mutation out-of-limit, and the alarm functions comprise TV disconnection alarm, TV abnormal alarm, TA disconnection alarm, TA measurement and TA protection difference current out-of-limit alarm.
Further, the TA current out-of-limit switching condition includes: when I is max ＞1.1I e When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA; corresponding alarm exit and alarm indicator light actions are simultaneously stored in the event record, wherein I max Is the maximum current, I e Rated current; and simultaneously starting a wave recording function.
Further, the TA current second harmonic content out-of-limit switching condition includes: when I max_2h ＞0.05I m &I m ＞0.2I e When the device starts to measure the TA and switches to the protection TA, the active power output of the device should be the active power calculated by the protection TA, wherein I max_2h Is the maximum second harmonic current, I m For measuring the current of the mutual inductor of the stage I e Rated current; corresponding actions of the alarm outlet and the alarm indicator light are stored in the event record; and simultaneously starting a wave recording function.
Further, the negative-sequence current switching condition of the TA current includes: when I 2m ＞0.06I e When the device starts to measure the TA and switches to the protection TA, the active power output of the device should be the active power calculated by the protection TA, wherein I 2m Measuring the negative sequence current of the transformer; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; and simultaneously starting a wave recording function.
Further, the TA current transient out-of-limit switching condition includes: when I is max(n) -I max(n-1) ＞0.2I e When the device starts to measure the TA and switches to the protection TA, the active power output of the device should be the active power calculated by the protection TA, wherein I max(n) Is a current at time n, I max(n-1) Is the current at time n-1, I e Rated current; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; and simultaneously starting a wave recording function.
Further, the TV disconnection warning includes: when U is turned 1 (Positive sequence voltage) < 20V&I max ＞5％I e Or U 1 (negative sequence voltage) > 2.5V, the device reports TV disconnection, and then the corresponding TV disconnection outlet and indicator lamp are actuated and simultaneously stored in the event record, wherein I max Is the maximum current, I e A rated current.
Further, the TV abnormal alarm includes: when TV1U 1 -TV2 U 1 > 2.5V or TV1U 1.max -TV2U 1.max When the voltage is more than 2.5V, the device reports TV abnormity, then corresponding alarm outlet and indicator lamp act, TV switching is started simultaneously, and the TV switching is stored in event record, wherein TV1U 1 For positive sequence voltage of the first group of transformers, TV 2U 1 Positive sequence voltage, TV1U, of a second group of transformers 1.max Maximum positive sequence voltage, TV 2U, of the first group of transformers 1.max The maximum positive sequence voltage of the second group of mutual inductors.
Further, the TA disconnection warning includes: when 3I 0 ＞25％I max +5％I e &When the three-phase four-wire system is adopted, the device reports TA wire break, and then the corresponding TA wire break outlet and the indicator lamp act and are simultaneously stored in an event record, and the event record comprisesIn (I) 0 Is a zero sequence current, I max Maximum current, I e The rated current.
Further, the measuring TA and protection TA differential flow out-of-limit alarm includes: when I is max –I m.max ＞5％I m.max &I m.max ＞30％I e When the device reports the out-of-limit alarm of the difference flow between the measured TA and the protected TA, then, the corresponding alarm outlet and the indicator lamp act and are simultaneously stored in the event record, wherein, I max Is the maximum current, I m.max Maximum measurement of mutual inductor current, I e Is the rated current.
Example 1
In this embodiment, the inrush current generated by the transformer in operation satisfies I max ＞1.1I e When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; simultaneously starting a wave recording function; satisfy I max_2h ＞0.05I m &I m ＞0.2I e When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA; corresponding actions of the alarm outlet and the alarm indicator light are stored in the event record; simultaneously starting a wave recording function; satisfy I 2m ＞0.06I e When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; simultaneously starting a wave recording function; satisfy I max(n) -I max(n-1) ＞0.2I e When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA; corresponding actions of an alarm outlet and an alarm indicator lamp are stored in an event record and a wave recording function is started at the same time, and the device starts a measurement TA and switches the measurement TA to a protection TA after the switching condition is met, so that the stability of the coordination control of the generator set is kept, and the problem of unit tripping caused by unit power oscillation and serious conditions is solved; and when the condition of the alarm function is satisfied, the corresponding function can be realizedThe TV disconnection outlet and the indicator light action, and the corresponding alarm outlet and the indicator light action.
Specifically, the inrush current generated by the transformer in operation satisfies U 1 (Positive sequence voltage) < 20V&I max ＞5％I e Or U 1 When the negative sequence voltage is greater than 2.5V, the device reports the TV disconnection, and then, the corresponding TV disconnection outlet and the indicator lamp act and are simultaneously stored in the event record; satisfy TV1U 1 -TV2 U 1 2.5V or TV1U 1.max -TV2 U 1.max When the voltage is more than 2.5V, the device reports TV abnormity, then, corresponding alarm outlets and indicator lamps act, TV switching is started at the same time, and the TV switching is stored in event records; satisfies when 3I 0 ＞25％I max +5％I e &When the three-phase four-wire system is carried out, the device reports TA wire breakage, and then, a corresponding TA wire breakage outlet and an indicator lamp act and are simultaneously stored in an event record; satisfy when I max –I m.max ＞5％I m.max &I m.max ＞30％I e When the device reports the out-of-limit alarm of the difference flow between the measured TA and the protected TA, and then, the corresponding alarm outlet and the indicator lamp act and are simultaneously stored in the event record.
The above description is intended to be illustrative of the preferred embodiment of the present invention and should not be taken as limiting the invention, but rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
Claims (1)
1. A method for eliminating inrush current influence in coordinated control of a generator set is characterized by comprising logic judgment for identifying inrush current possible time and fault time, wherein the logic judgment comprises switching conditions and alarm functions, the switching conditions comprise TA current out-of-limit, TA secondary harmonic content out-of-limit, TA current negative sequence current out-of-limit and TA current mutation out-of-limit, and the alarm functions comprise TV disconnection alarm, TV abnormal alarm, TA disconnection alarm, measurement TA and protection TA differential current out-of-limit alarm; the TA current out-of-limit switching conditions include: when in use
＞1.1
When the device starts to measure the TA and switches to the protection TA, the active power output of the device is the active power calculated by the protection TA; corresponding alarm exit and alarm indicator lamp actions are simultaneously stored in the event record, wherein
The current is the maximum current, and the current is the maximum current,
rated current; simultaneously starting a wave recording function; the TA current second harmonic content out-of-limit switching condition comprises the following steps: when in use
＞0.05
&
＞0.2
When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA, wherein,
for the maximum of the second harmonic current,
in order to measure the current of the level transformer,
rated current; the corresponding alarm outlet and the alarm indicator lamp act,simultaneously storing in an event record; simultaneously starting a wave recording function; the negative-sequence current out-of-limit switching condition of the TA current comprises: when in use
＞0.06
When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA, wherein,
measuring the negative sequence current of the transformer; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; simultaneously starting a wave recording function; the TA current abrupt change amount out-of-limit switching condition comprises the following steps: when in use
-
＞0.2
When the device starts to measure the TA and switches to the protection TA, the output of the active power of the device is the active power calculated by the protection TA, wherein,
the current is applied at the time n,
the current at the time n-1 is,
rated current; corresponding alarm exit and alarm indicator lamp actions are stored in the event record; the TV abnormal alarm packetComprises the following steps: when TV1U 1-TV 2U 1 > 2.5V or TV1
-TV2 
If the voltage is more than 2.5V, the device reports TV abnormity, then corresponding alarm exit and indicator lamp act, and the corresponding alarm exit and indicator lamp act are simultaneously stored in an event record, wherein, the TV1
For the positive sequence voltage of the first group of transformers, TV2
Positive sequence voltage of a second group of transformers, TV1
Maximum positive sequence voltage of the first group of transformers, TV2
The maximum positive sequence voltage of the second group of mutual inductors; the TA disconnection warning comprises the following steps: when in use
＞25%
+5%
&When the three-phase four-wire system is adopted, the device reports TA disconnection, then, the corresponding TA disconnection outlet and the indicator lamp act and are simultaneously stored in an event record, wherein,
is a zero-sequence current, and is a zero-sequence current,
the maximum current of the electric current is set,
the rated current.
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| CN103944467B (en) * | 2014-04-02 | 2016-05-18 | 南京保合太和电力科技有限公司 | generator power transmitting system and method |
| CN106226593B (en) * | 2016-08-31 | 2023-06-16 | 江苏大唐国际吕四港发电有限责任公司 | Intelligent active power transmitting device of generator |
| CN108983096B (en) * | 2018-07-27 | 2021-05-07 | 国电南瑞南京控制系统有限公司 | Method for determining power of high-voltage motor and measuring device |
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