CN115728699A - Fault diagnosis method for opening triangular secondary circuit of voltage transformer - Google Patents
Fault diagnosis method for opening triangular secondary circuit of voltage transformer Download PDFInfo
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Abstract
The invention discloses a fault diagnosis method for an open triangular secondary circuit of a voltage transformer, which comprises the steps of establishing a voltage current representation of a common fault of the open triangular secondary circuit of the voltage transformer according to a typical fault type of the open triangular secondary circuit of the voltage transformer; determining a mapping relation of voltage and current representations of common faults of the open delta secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit current, the amplitude of the three-phase voltage of the open delta secondary side and the phase of the three-phase voltage of the open delta secondary side, and judging typical fault types; according to the method, the fault state voltage and current representation is adopted, the intelligent diagnosis of the open triangular secondary circuit fault is realized, and the abnormity of the open triangular secondary circuit of the voltage transformer is efficiently identified.
Description
Technical Field
The invention relates to a fault diagnosis method for an open triangular secondary circuit of a voltage transformer, and belongs to the technical field of power system protection.
Background
The open triangle secondary circuit of the voltage transformer is formed by connecting the secondary windings of the three-phase voltage transformer end to end, but not connecting the secondary windings at last to form an open triangle. Under the normal operating condition, three-phase voltage is balanced, and the vector sum is zero, therefore open delta connection can not gather voltage, but when the system takes place asymmetric ground connection short circuit once, open delta connection will gather zero sequence voltage.
The voltage transformer is a voltage source with extremely low internal resistance, the load impedance is very large when the voltage transformer normally operates, the secondary side only has very small load current, and when the secondary side is in short circuit, the load impedance is zero, so that very large short-circuit current is generated, and the voltage transformer can be burnt out or even endangered the personal safety. Therefore, an air switch is arranged in a star-shaped wiring loop of the secondary side of the voltage transformer to cut off a short-circuit point, the voltage drop collected by the protection device is zero after the air switch is tripped, and a worker can find the voltage drop in time.
However, if the secondary side of the voltage transformer adopts a loop of triangular wiring, zero sequence voltage cannot be found in time even if the circuit is opened, because zero sequence voltage is zero during normal operation, and if the system is asymmetrically grounded during the period, the zero sequence voltage cannot be monitored by a protection device in the protection cabinet, the state of the primary system cannot be correctly reflected, and protection is rejected; if the open triangular secondary circuit of the voltage transformer is not provided with an empty switch, primary equipment and secondary equipment are damaged or personal injury is caused when a short-circuit fault occurs in the circuit.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a fault diagnosis method for an open triangular secondary circuit of a voltage transformer.
In order to achieve the above object, the present invention provides a fault diagnosis method for an open-delta secondary circuit of a voltage transformer, comprising the following steps:
step 1: establishing voltage and current representations of common faults of the open triangular secondary circuit of the voltage transformer according to typical fault types of the open triangular secondary circuit of the voltage transformer;
step 2: collecting an A phase voltage, a B phase voltage, a C phase voltage, an open delta secondary circuit voltage and an open delta secondary circuit current of an open delta winding secondary circuit in real time;
and 3, step 3: calculating the amplitude of the secondary side three-phase voltage of the open delta winding and the phase of the secondary side three-phase voltage of the open delta winding; determining a mapping relation of voltage and current representations of common faults of the open delta secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit current, the amplitude of the three-phase voltage of the open delta secondary side and the phase of the three-phase voltage of the open delta secondary side, and judging typical fault types;
and 4, step 4: and controlling the action and the return of the signal relay and giving an alarm.
Preferentially, in the step 1, typical fault types of the open triangular secondary circuit of the voltage transformer comprise circuit disconnection, outgoing line short circuit and polarity reversal;
the voltage and current characterization method for common faults of the open triangular secondary circuit of the voltage transformer comprises the following steps:
if the typical fault type of the secondary loop is loop disconnection, the open triangle secondary loop current i d =0A; when the break point is led out from the external, the A phase voltage u of the secondary loop of the open delta winding da Phase u of B phase db And a phase u of C voltage dc All are not 0, open triangular secondary loop current i d =0A; when the circuit is disconnected and the fault interval is in the secondary side of the voltage transformerWhen the voltage is between the local terminal box and the open delta winding secondary circuit A phase voltage u da Phase u of B phase db And a phase u of C voltage dc Any one of which is 0V, open delta secondary loop current i d ＝0A；
If the typical fault type of the open triangular secondary circuit of the voltage transformer is short circuit of an external outgoing line, the voltage u at the outlet of the open triangular secondary circuit d The outlet voltage Udset of the open triangular secondary circuit is increased before the short circuit of the outgoing line, and the current i of the open triangular secondary circuit is increased d The open triangular secondary loop current Idset before the external outgoing line is increased compared with the short-circuit point;
if the typical fault type of the open triangular secondary circuit of the voltage transformer is a local wiring short circuit, the outlet voltage u of the open triangular secondary circuit d The voltage Udset of the outlet of the open delta secondary circuit is increased compared with the voltage Udset of the outlet of the open delta secondary circuit before the short circuit of the leading-out wire, and the voltage u of the phase A of the open delta winding secondary circuit is increased da B-phase voltage u db C phase voltage u dc The voltage measurement value of the terminals on both sides of the short-circuit point is reduced compared with that before the short circuit; if the outgoing line short-circuit fault section is in turn short circuit between the secondary side of the voltage transformer and the local terminal box or between the open triangle secondary winding of the voltage transformer, the outlet voltage u of the open triangle secondary loop d Compared with the outlet voltage Udset of the open triangular secondary circuit before the short circuit of the outgoing line, the A-phase voltage u of the open triangular winding secondary circuit is increased da Phase u of B phase db C phase voltage u dc The voltage measured value of the terminals at the two sides of the short circuit point is reduced compared with the voltage measured value of the terminals at the two sides of the short circuit point before short circuit;
if the typical fault type of the open triangular secondary circuit of the voltage transformer is reverse polarity connection, the A-phase voltage u of the open triangular winding secondary circuit is equal to the voltage u of the open triangular winding secondary circuit da The phase voltage is changed into a phase voltage corresponding to two times A, and the phase voltage u of the open delta winding secondary circuit is changed into a phase voltage u of the open delta winding secondary circuit db The phase voltage is changed into the phase voltage corresponding to two times B, and the phase voltage u of the secondary circuit C of the open delta winding is changed into the phase voltage corresponding to two times B dc The phase voltage is changed into the phase voltage corresponding to two times C, and the phase voltage u of the open delta winding secondary circuit A at the moment da Phase u of B phase db And a C-phase voltage u dc The phase difference is not equal to 120.
Preferentially, step 2: the method comprises the following steps of collecting the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit voltage and the open delta secondary circuit current of the open delta winding secondary circuit in real time, and realizing the following steps:
the voltage and current sampling circuit is used for collecting the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit voltage and the open delta secondary circuit current of the open delta winding secondary circuit in real time;
the voltage and current sampling circuit comprises 4 voltage samples and 1 current sample, the voltage samples are connected to corresponding terminals of the local terminal box of the voltage transformer, the current samples are connected to an external outgoing line of an open triangular secondary circuit of the local terminal box of the voltage transformer and used for measuring phase voltage u of an A phase of the open triangular secondary circuit da Phase u of B phase db C phase voltage u dc Outlet voltage u of open triangular secondary loop d And open delta secondary loop current i d 。
Preferentially, in the step 3, the amplitude of the secondary side three-phase voltage of the open delta winding and the phase of the secondary side three-phase voltage of the open delta winding are calculated, and the method is realized through the following steps:
the open delta winding secondary circuit A phase voltage u da Phase u of B phase db C phase voltage u dc Outlet voltage u of open triangular secondary loop d And open delta secondary loop current i d Substituting the u in the following formula, and calculating and obtaining the amplitude of the A phase voltage, the amplitude of the B phase voltage, the amplitude of the C phase voltage, the initial phase of the A phase voltage, the initial phase of the B phase voltage and the initial phase of the C phase voltage:
wherein U is the instantaneous value of the voltage, U is the amplitude of the voltage, theta is the initial phase, t is the time,
voltage rate of change, ω angular frequency;
for power frequency circuits, angular frequency ω =2 π f =100 π;
when the sampling period of the sampling circuit is T c In the time, the voltage u of the A phase of the secondary loop of the open delta winding is added da Phase u of B phase db C phase voltage u dc Outlet voltage u of open triangular secondary loop d And open delta secondary loop current i d Substituting u in the following formula, and calculating and obtaining the amplitude of the A phase voltage, the amplitude of the B phase voltage, the amplitude of the C phase voltage, the phase of the A phase voltage, the phase of the B phase voltage and the phase of the C phase voltage:
wherein U is the instantaneous value of the voltage, U is the amplitude of the voltage, ω is the angular frequency, t is the time, θ is the initial phase 1 = ω T + θ, u (T) being the sampling period T c Value of the voltage sample at u (T-T) c ) The amplitude U and the phase theta of the sampled voltage can be calculated according to the formula 1 ；
Defining open delta secondary circuit a-phase voltage u da Initial phase of 0 °:
in the formula u da (t) is the A phase voltage u under the current sampling period da (t-T c ) When the sampling voltage satisfies the formula (3), the current time is used as the initial time, and u is the A phase voltage in the last sampling period da Is 0 deg..
Preferentially, in step 3, according to the a phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit current, the amplitude of the open delta winding secondary side three-phase voltage and the phase of the open delta winding secondary side three-phase voltage, a mapping relation with the common fault voltage and current representation of the open delta secondary circuit of the voltage transformer is determined, a typical fault type is judged, and the method is realized through the following steps:
after a typical fault type is determined, determining a fault section according to an A phase voltage, a B phase voltage, a C phase voltage, an open delta secondary circuit voltage and an open delta secondary circuit current of the open delta winding secondary circuit;
determining a fault interval, comprising:
when the typical fault type is circuit disconnection, if the amplitude of the secondary side three-phase voltage of the open triangle of the voltage transformer is a normal value, the fault section of the open triangle secondary circuit disconnection of the voltage transformer is an external outgoing line; if the amplitude of the phase voltage of the open triangular secondary side of the voltage transformer is 0V, the broken fault section of the open triangular secondary circuit of the voltage transformer is between the secondary side of the voltage transformer and the local terminal box;
when the typical fault type is the short circuit of the outgoing line, if the open triangular secondary loop current i d The short-circuit point is increased before the external outgoing line, and the fault section of the outgoing line short circuit is the external outgoing line; if the voltage amplitude of the open triangular secondary side phase of the voltage transformer is reduced, the fault section of the short circuit of the outgoing line is the turn-to-turn of the voltage transformer; if the amplitude of the three-phase voltage of the open triangular secondary side of the voltage transformer is normal and the current i of the open triangular secondary loop d And if the voltage transformer is not increased, the fault section of the short circuit of the outgoing line is between the secondary side of the voltage transformer and the local terminal box.
Preferentially, in the step 4, the action and the return of the signal relay are controlled, the alarm is given, and the method is realized through the following steps:
after the typical fault type of the secondary circuit of the open delta winding is determined, a fault signal is opened through a normally open node of a signal relay; and (4) sending the fault signal to a central control DCS (distributed control system), and carrying out photon board reminding according to the sequential probability fault signal.
A voltage transformer opening triangle secondary circuit fault diagnosis system comprises:
the characterization establishing module is used for establishing voltage and current characterization of common faults of the open triangular secondary circuit of the voltage transformer according to typical fault types of the open triangular secondary circuit of the voltage transformer;
the sampling module is used for the voltage and current sampling circuit to collect the A phase voltage, the B phase voltage, the C phase voltage, the voltage of the open delta secondary loop and the current of the open delta secondary loop in real time;
the calculation module is used for calculating the amplitude of the three-phase voltage on the secondary side of the open delta winding and the phase of the three-phase voltage on the secondary side of the open delta winding;
the judging module is used for determining a mapping relation of the voltage representation and the common fault voltage and current representation of the open delta secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit current, the amplitude of the secondary side three-phase voltage of the open delta winding and the phase of the secondary side three-phase voltage of the open delta winding, and judging a typical fault type;
and the output module is used for controlling the action and the return of the signal relay and giving an alarm.
Preferably, the judging module is configured to determine a fault section according to an a-phase voltage, a B-phase voltage, a C-phase voltage, an open delta secondary circuit voltage, and an open delta secondary circuit current of the open delta winding secondary circuit after determining the typical fault type.
An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of any of the above methods when executing the program.
A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method of any of the above.
The invention achieves the following beneficial effects:
according to the invention, by combining the three-phase voltage and the loop current of the open triangular winding and representing the voltage and the current in a fault state, the intelligent diagnosis of the fault of the open triangular secondary loop is realized, and the abnormity of the open triangular secondary loop of the voltage transformer is efficiently identified.
Drawings
FIG. 1 is a schematic wiring diagram of the present invention;
FIG. 2 is a fault diagnosis logic diagram of an embodiment of the present invention;
fig. 3 is a schematic diagram of the system of the present invention.
Detailed Description
The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
The invention provides a fault diagnosis method for an open triangular secondary circuit of a voltage transformer, which comprises the following steps of:
step 1: establishing voltage and current representations of common faults of the open triangular secondary circuit of the voltage transformer according to typical fault types of the open triangular secondary circuit of the voltage transformer;
step 2: collecting an A phase voltage, a B phase voltage, a C phase voltage, an open delta secondary circuit voltage and an open delta secondary circuit current of an open delta winding secondary circuit in real time;
and 3, step 3: calculating the amplitude of the secondary side three-phase voltage of the open delta winding and the phase of the secondary side three-phase voltage of the open delta winding; determining a mapping relation represented by common fault voltage and current of the open triangular secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open triangular secondary circuit current, the amplitude of the secondary side three-phase voltage of the open triangular winding and the phase of the secondary side three-phase voltage of the open triangular winding, and judging a typical fault type;
and 4, step 4: and the controller is used for controlling the action and the return of the signal relay, and the fault alarm signal is sent to the central control DCS system through the switching value output quantity.
The method for diagnosing the fault of the open triangular secondary circuit of the voltage transformer is described in detail below according to specific parameters of the voltage transformer of the GCB cabinet of a certain power plant in China and by combining the attached drawings. The parameters of the voltage transformer are as follows:
transformation ratio:
loop 1:
loop 2:
an open triangular loop:
FIG. 1 shows a system wiring diagram of the electric quantity required by the open-delta secondary circuit fault diagnosis method, and the three-phase voltages u, B and C are measured in real time by adding four voltage measuring points at the terminals TV-a ', TV-x', TV-y 'and TV-z' of the local terminal boxes of the voltage transformer da 、u db 、u dc And open triangular secondary loop voltage u d (ii) a An induction coil is additionally arranged on a leading-out wire of the opening triangular secondary loop to measure the current i of the opening triangular secondary loop in real time d 。
Fig. 2 shows a fault diagnosis logic diagram, and the mapping relation with the actual physical fault is determined by the controller according to the calculated voltage and current states, so as to judge the fault state.
In the step 1, typical fault types of an open triangular secondary circuit of the voltage transformer comprise circuit disconnection, outgoing line short circuit and polarity reversal;
in the step 1, typical fault types of an open triangular secondary circuit of the voltage transformer comprise circuit disconnection, outgoing line short circuit and polarity reversal;
the voltage and current characterization method for common faults of the open triangular secondary circuit of the voltage transformer comprises the following steps:
if the typical fault type of the secondary loop is loop disconnection, the open triangle secondary loop current i d =0A; when the break point is led out from the external, the A phase voltage u of the secondary loop of the open delta winding da Phase u of B phase db And a phase u of C voltage dc All are not 0, open triangular secondary loop current i d =0A; when the circuit disconnection fault interval is between the secondary side of the voltage transformer and the local terminal boxThe voltage u of the open delta winding secondary loop A phase da Phase u of B phase db And a phase u of C voltage dc Any one of which is 0V, open delta secondary loop current i d ＝0A；
If the typical fault type of the open triangular secondary circuit of the voltage transformer is the short circuit of an external outgoing line, the voltage u at the outlet of the open triangular secondary circuit d The outlet voltage Udset of the open triangular secondary circuit is increased before the short circuit of the outgoing line, and the current i of the open triangular secondary circuit is increased d The current Idset of the open triangular secondary loop is increased compared with the current Idset of the open triangular secondary loop before the external outgoing line of the short-circuit point;
if the typical fault type of the open triangular secondary circuit of the voltage transformer is a local wiring short circuit, the outlet voltage u of the open triangular secondary circuit d The voltage Udset of the outlet of the open delta secondary circuit is increased compared with the voltage Udset of the outlet of the open delta secondary circuit before the short circuit of the leading-out wire, and the voltage u of the phase A of the open delta winding secondary circuit is increased da B-phase voltage u db C phase voltage u dc The voltage measurement value of the terminals on both sides of the short-circuit point is reduced compared with that before the short circuit; if the outgoing line short-circuit fault section is in turn short circuit between the secondary side of the voltage transformer and the local terminal box or between the open triangle secondary winding of the voltage transformer, the outlet voltage u of the open triangle secondary loop d The voltage Udset of the outlet of the open delta secondary circuit is increased compared with the voltage Udset of the outlet of the open delta secondary circuit before the short circuit of the leading-out wire, and the voltage u of the phase A of the open delta winding secondary circuit is increased da Phase u of B phase db C-phase voltage u dc The voltage measurement value of the terminals on both sides of the short-circuit point is reduced compared with that before the short circuit;
if the typical fault type of the open delta secondary circuit of the voltage transformer is reverse polarity connection, the A-phase voltage u of the open delta winding secondary circuit da The phase voltage is changed into a phase voltage corresponding to two times A, and the phase voltage u of the open delta winding secondary circuit is changed into a phase voltage u of the open delta winding secondary circuit db The phase voltage is changed into a phase voltage corresponding to two times B, and the phase voltage u of the open delta winding secondary circuit C dc The phase voltage is changed into the phase voltage corresponding to two times C, and the phase voltage u of the open delta winding secondary circuit A at the moment da B-phase voltage u db And a phase u of C voltage dc The phase difference is not equal to 120.
And the controller is used for controlling the action and the return of the signal relay, and the fault alarm signal is sent to the central control DCS system through the switching value output quantity.
After the secondary circuit of the open delta winding is determined to be in fault, the controller opens a fault signal through a normally open node of the signal relay, the fault signal is sent to the central control DCS system, and operation and maintenance personnel are reminded to take relevant measures through the SOE or the photon board.
In conclusion, by adopting the method, the circuit disconnection, the outgoing line short circuit and the polarity reverse connection fault of the open triangular secondary circuit can be effectively distinguished, the safe and stable operation of the secondary circuit of the voltage transformer is ensured, and the reliability of the relay protection device is further ensured.
Example 2
The invention provides a fault diagnosis device for an open triangular secondary circuit of a voltage transformer, which comprises a sampling module, a calculation module, a judgment module and an output module.
Fig. 3 shows a configuration diagram of a failure diagnosis apparatus of the embodiment,
a voltage transformer opening triangle secondary circuit fault diagnosis system comprises:
the characterization establishing module is used for establishing voltage and current characterization of common faults of the open triangular secondary circuit of the voltage transformer according to typical fault types of the open triangular secondary circuit of the voltage transformer;
the sampling module is used for the voltage and current sampling circuit to collect the A phase voltage, the B phase voltage, the C phase voltage, the voltage of the open delta secondary loop and the current of the open delta secondary loop in real time;
the calculation module is used for calculating the amplitude of the three-phase voltage on the secondary side of the open delta winding and the phase of the three-phase voltage on the secondary side of the open delta winding;
the judging module is used for determining a mapping relation with the common fault voltage and current representation of the open triangular secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open triangular secondary circuit current, the amplitude of the secondary side three-phase voltage of the open triangular winding and the phase of the secondary side three-phase voltage of the open triangular winding, and judging the typical fault type;
and the output module is used for controlling the action and the return of the signal relay, giving an alarm and outputting an alarm signal to the DSC background by using the normally open node.
To illustrate the diagnostic method of the present invention, the following example is given, which illustrates only a few open three-set secondary circuit cases:
1) When the open triangular loop normally works, because the three-phase voltage is not completely symmetrical, the open triangular outlet has unbalanced voltage and is accompanied by outlet current, but the unbalanced voltage is smaller than a program opening threshold, and the fault diagnosis device cannot malfunction.
2) When the phase-to-phase short circuit of the open triangular loop A and the phase-to-phase short circuit of the open triangular loop B occurs, only the phase-to-phase short circuit current exists, the outlet current is smaller than the current fixed value, the effective value of the outlet voltage of the open triangular loop is 33.3V, the voltage of the phase-to-phase measuring points A and B is unchanged, the effective value of the voltage is 33.3V, the condition of the outlet of the outgoing line short circuit (in-situ wiring short circuit) is met, and the device can sensitively respond to the fault and send an alarm signal.
3) When the C phase of the open triangular loop is in turn-to-turn short circuit, the outlet current is smaller than the current fixed value, the voltage of the open triangular outlet is increased at the moment, the voltage of the C phase measuring point is reduced, the outlet condition of outgoing line short circuit (in-situ wiring short circuit) is met, and the device can correctly distinguish fault types and send out alarm signals.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several 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.
Claims (10)
1. A fault diagnosis method for an open triangular secondary circuit of a voltage transformer is characterized by comprising the following steps:
step 1: establishing voltage and current representations of common faults of the open triangular secondary circuit of the voltage transformer according to typical fault types of the open triangular secondary circuit of the voltage transformer;
step 2: collecting an A phase voltage, a B phase voltage, a C phase voltage, an open delta secondary circuit voltage and an open delta secondary circuit current of an open delta winding secondary circuit in real time;
and 3, step 3: calculating the amplitude of the secondary side three-phase voltage of the open delta winding and the phase of the secondary side three-phase voltage of the open delta winding; determining a mapping relation represented by common fault voltage and current of the open triangular secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open triangular secondary circuit current, the amplitude of the secondary side three-phase voltage of the open triangular winding and the phase of the secondary side three-phase voltage of the open triangular winding, and judging a typical fault type;
and 4, step 4: and controlling the action and the return of the signal relay and giving an alarm.
2. The method for diagnosing the fault of the open triangular secondary circuit of the voltage transformer as claimed in claim 1, wherein in the step 1, typical fault types of the open triangular secondary circuit of the voltage transformer comprise circuit disconnection, outgoing line short circuit and polarity reversal;
the voltage and current characterization method for common faults of the open triangular secondary circuit of the voltage transformer comprises the following steps:
if the typical fault type of the secondary loop is loop disconnection, the open-delta secondary loop current i d =0A; when the break point is led out from the external, the A phase voltage u of the secondary loop of the open delta winding da Phase u of B phase db And a phase u of C voltage dc All are not 0, open triangular secondary loop current i d =0A; when the circuit disconnection fault interval is between the secondary side of the voltage transformer and the local terminal box, the A-phase voltage u of the open delta winding secondary circuit is equal to the voltage u of the open delta winding secondary circuit da B-phase voltage u db And a C-phase voltage u dc Any one of which is 0V, open delta secondary loop current i d ＝0A；
If the typical fault type of the open triangular secondary circuit of the voltage transformer is the short circuit of an external outgoing line, the voltage u at the outlet of the open triangular secondary circuit d The outlet voltage Udset of the open triangular secondary circuit is increased and the opening is opened before the short circuit of the outgoing lineTriangular secondary loop current i d The open triangular secondary loop current Idset before the external outgoing line is increased compared with the short-circuit point;
if the typical fault type of the open triangular secondary circuit of the voltage transformer is in-situ wiring short circuit, the outlet voltage u of the open triangular secondary circuit d Compared with the outlet voltage Udset of the open triangular secondary circuit before the short circuit of the outgoing line, the A-phase voltage u of the open triangular winding secondary circuit is increased da Phase u of B phase db C phase voltage u dc The voltage measurement value of the terminals on both sides of the short-circuit point is reduced compared with that before the short circuit; if the outgoing line short-circuit fault section is in turn short circuit between the secondary side of the voltage transformer and the local terminal box or between the open triangle secondary winding of the voltage transformer, the outlet voltage u of the open triangle secondary loop d Compared with the outlet voltage Udset of the open triangular secondary circuit before the short circuit of the outgoing line, the A-phase voltage u of the open triangular winding secondary circuit is increased da Phase u of B phase db C phase voltage u dc The voltage measured value of the terminals at the two sides of the short circuit point is reduced compared with the voltage measured value of the terminals at the two sides of the short circuit point before short circuit;
if the typical fault type of the open triangular secondary circuit of the voltage transformer is reverse polarity connection, the A-phase voltage u of the open triangular winding secondary circuit is equal to the voltage u of the open triangular winding secondary circuit da The phase voltage is changed into a phase voltage corresponding to two times A, and the phase voltage u of the open delta winding secondary circuit is changed into a phase voltage u of the open delta winding secondary circuit db The phase voltage is changed into a phase voltage corresponding to two times B, and the phase voltage u of the open delta winding secondary circuit C dc The phase voltage is changed into the phase voltage corresponding to two times C, and the phase voltage u of the open delta winding secondary circuit A at the moment da Phase u of B phase db And a C-phase voltage u dc The phase difference is not equal to 120.
3. The method for diagnosing the fault of the open triangular secondary circuit of the voltage transformer according to claim 1, wherein the step 2 is as follows: the method comprises the following steps of collecting the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit voltage and the open delta secondary circuit current of an open delta winding secondary circuit in real time, and realizing the following steps:
the voltage and current sampling circuit is used for collecting the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit voltage and the open delta secondary circuit current of the open delta winding secondary circuit in real time;
the voltage and current sampling circuit comprises 4 voltage samples and 1 current sample, the voltage samples are connected to corresponding terminals of the voltage transformer local terminal box, the current samples are connected to external leading-out wires of the open delta secondary circuit of the voltage transformer local terminal box and used for measuring the A phase voltage u of the open delta secondary circuit da Phase u of B phase db C phase voltage u dc Outlet voltage u of open triangular secondary loop d And open delta secondary loop current i d 。
4. The method for diagnosing the fault of the open triangular secondary circuit of the voltage transformer according to claim 3,
in step 3, calculating the amplitude of the secondary side three-phase voltage of the open delta winding and the phase of the secondary side three-phase voltage of the open delta winding, and realizing the method through the following steps:
the open delta winding secondary circuit A phase voltage u da Phase u of B phase db C-phase voltage u dc Outlet voltage u of open triangular secondary loop d And open delta secondary loop current i d Substituting u in the following formula, and calculating and obtaining the amplitude of the A phase voltage, the amplitude of the B phase voltage, the amplitude of the C phase voltage, the initial phase of the A phase voltage, the initial phase of the B phase voltage and the initial phase of the C phase voltage:
wherein U is an instantaneous value of the voltage, U is an amplitude of the voltage, theta is an initial phase, t is time,
is the voltage rate of change, ω is the angular frequency;
for power frequency circuits, angular frequency ω =2 π f =100 π;
when the sampling period of the sampling circuit is T c Then, the open delta winding is woundSecondary loop A phase voltage u da Phase u of B phase db C phase voltage u dc Outlet voltage u of open triangular secondary loop d And open delta secondary loop current i d Substituting the u in the following formula, and calculating and obtaining the amplitude of the A phase voltage, the amplitude of the B phase voltage, the amplitude of the C phase voltage, the phase of the A phase voltage, the phase of the B phase voltage and the phase of the C phase voltage:
wherein U is the instantaneous value of the voltage, U is the amplitude of the voltage, ω is the angular frequency, t is the time, θ is the initial phase, θ is the phase of the phase-locked loop 1 = ω T + θ, u (T) being the sampling period T c Value of the voltage sample at u (T-T) c ) The amplitude U and the phase theta of the sampled voltage can be calculated according to the formula 1 ；
Defining open delta secondary circuit a-phase voltage u da Initial phase of 0 °:
in the formula u da (t) is the A phase voltage u under the current sampling period da (t-T c ) When the sampling voltage satisfies the formula (3), the current time is used as the initial time, and u is the phase voltage in the last sampling period da Is 0 deg..
5. The method for diagnosing the fault of the open triangular secondary circuit of the voltage transformer as claimed in claim 4,
in step 3, according to the phase voltage A, the phase voltage B, the phase voltage C, the voltage of the open triangular secondary loop, the current of the open triangular secondary loop, the amplitude of the secondary side three-phase voltage of the open triangular winding and the phase of the secondary side three-phase voltage of the open triangular winding, a mapping relation with the common fault voltage and current representation of the open triangular secondary loop of the voltage transformer is determined, a typical fault type is judged, and the method is realized through the following steps:
after the typical fault type is determined, determining a fault interval according to the A phase voltage, the B phase voltage, the C phase voltage, the open delta secondary circuit voltage and the open delta secondary circuit current of the open delta winding secondary circuit;
determining a fault interval, comprising:
when the typical fault type is circuit disconnection, if the amplitude of the secondary side three-phase voltage of the open triangle of the voltage transformer is a normal value, the fault section of the open triangle secondary circuit disconnection of the voltage transformer is an external outgoing line; if the amplitude of the phase voltage of the secondary side of the open triangle of the voltage transformer is 0V, the broken fault section of the open triangle secondary circuit of the voltage transformer is between the secondary side of the voltage transformer and the local terminal box;
when the typical fault type is the short circuit of the outgoing line, if the open triangular secondary loop current i d The short-circuit point is increased before the external outgoing line, and the fault section of the outgoing line short circuit is the external outgoing line; if the voltage amplitude of the open triangular secondary side phase of the voltage transformer is reduced, the fault section of the short circuit of the outgoing line is the turn-to-turn of the voltage transformer; if the amplitude of the three-phase voltage of the open triangular secondary side of the voltage transformer is normal and the current i of the open triangular secondary loop d And if the voltage transformer is not increased, the fault section of the short circuit of the outgoing line is between the secondary side of the voltage transformer and the local terminal box.
6. The open-delta secondary circuit fault diagnosis method for the voltage transformer as claimed in claim 1, wherein in step 4, the action and the return of the signal relay are controlled, and an alarm is given, which is realized by the following steps:
after the typical fault type of the secondary circuit of the open delta winding is determined, a fault signal is opened through a normally open node of a signal relay;
and (4) sending the fault signal to a central control DCS (distributed control system), and carrying out photon board reminding through a central control SOE (system on insulator) function.
7. The utility model provides a voltage transformer opening triangle secondary circuit fault diagnosis system which characterized in that includes:
the characterization establishing module is used for establishing voltage and current characterization of common faults of the open triangular secondary circuit of the voltage transformer according to typical fault types of the open triangular secondary circuit of the voltage transformer;
the sampling module is used for the voltage and current sampling circuit to acquire the phase voltage A, the phase voltage B, the phase voltage C, the voltage of the open triangular secondary loop and the current of the open triangular secondary loop in real time;
the calculation module is used for calculating the amplitude of the three-phase voltage on the secondary side of the open delta winding and the phase of the three-phase voltage on the secondary side of the open delta winding;
the judging module is used for determining a mapping relation with the common fault voltage and current representation of the open triangular secondary circuit of the voltage transformer according to the A phase voltage, the B phase voltage, the C phase voltage, the open triangular secondary circuit current, the amplitude of the secondary side three-phase voltage of the open triangular winding and the phase of the secondary side three-phase voltage of the open triangular winding, and judging the typical fault type;
and the output module is used for controlling the action and the return of the signal relay and giving an alarm.
8. The open delta secondary circuit fault diagnosis system of claim 7, wherein the judging module is configured to determine the fault section according to the open delta winding secondary circuit a-phase voltage, B-phase voltage, C-phase voltage, open delta secondary circuit voltage and open delta secondary circuit current after determining the typical fault type.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method of any of claims 1 to 8 are implemented when the processor executes the program.
10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 8.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116482581A (en) * | 2023-06-20 | 2023-07-25 | 广东电网有限责任公司佛山供电局 | Transformer substation voltage transformer opening triangle voltage secondary circuit tester |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116482581A (en) * | 2023-06-20 | 2023-07-25 | 广东电网有限责任公司佛山供电局 | Transformer substation voltage transformer opening triangle voltage secondary circuit tester |
| CN116482581B (en) * | 2023-06-20 | 2023-11-14 | 广东电网有限责任公司佛山供电局 | Transformer substation voltage transformer opening triangle voltage secondary circuit tester |
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