Summary of the invention
The objective of the invention is in order to overcome the deficiencies in the prior art part, proposed a kind of highly sensitive, quick action, the shunt reactor interturn short circuit protection zero sequence impedance method of discrimination that reliability is high.
Solution of the present invention is to utilize the split-phase type structure of the large-scale shunt reactor of electric system; according to its major failure is singlephase earth fault and shorted-turn fault; in turn-to-turn short circuit is differentiated, do not get rid of the situation of internal interface ground short circuit fault simultaneously, differentiate as the distinguishing rule of interturn short circuit protection zero sequence impedance.
Shunt reactor zero sequence loop as shown in Figure 2, wherein:
The K1-shorted-turn fault; K2-reactor internal ground fault; K3-district external ground fault.
(1) turn-to-turn short circuit K1
When reactor interturn short circuit, the zero sequence source is promptly sent homopolar power by reactor to system in reactor inside.As shown in Figure 3.This moment, the pass of residual voltage and zero-sequence current was U
0=-I
0JZ
S0, what port measured is the zero sequence impedance of system.
Z
S0---system's zero sequence impedance.
(2) inner singlephase earth fault K2
During the reactor internal ground fault, the zero sequence source is in reactor inside, and residual voltage and zero-sequence current relation are as shown in Figure 4.This moment the U of system
0=-I
0JZs
0, the leading residual voltage of zero-sequence current.What port measured is the zero sequence impedance of system.
(3) outside singlephase earth fault K3
During the outside singlephase earth fault of reactor, the zero sequence source is in the reactor outside, and the relation of residual voltage and zero-sequence current as shown in Figure 5.At this moment the U of system
0=I
0JZ
L0, zero-sequence current hysteresis residual voltage.What port measured is the zero sequence impedance of reactor.
Z
L0---the zero sequence impedance of reactor.
By above analysis as can be known: when turn-to-turn short circuit and inner singlephase earth fault and during outside singlephase earth fault zero sequence impedance, the zero sequence impedance of surveying turn-to-turn short circuit and inner singlephase earth fault on impedance plane fall within upper half, outside singlephase earth fault falls within bottom half.And system's zero sequence impedance generally has only tens Europe in electric system, and the zero sequence impedance of reactor generally reaches hundreds of Europe, X
L0>>Xs
0
Therefore during fault, can decide abort situation place (inner still in system) by the position in system zero sequence loop zero sequence source at reactor.So adopt the criterion of the zero sequence impedance circle of band offset characteristic in the specific implementation as the reactor interturn protection.
Simultaneously, interturn protection will escape under the nominal situation because residual voltage and the inconsistent zero-sequence current that causes of three-phase TA that imbalance of three-phase voltage causes.For guaranteeing to demonstrate,prove the sensitivity of interturn protection, the zero sequence monitor current setting valve of protection should be less.In addition, when reactor drops, make the interturn protection malfunction for preventing excitation surge current, interturn protection zero sequence monitor current adopts the definite value of anti-time limit characteristic when reactor drops.
The zero sequence impedance circle criterion (see figure 6) of band offset characteristic is adopted in the reactor interturn protection, and its criterial equation group is:
1)3I
0>I
mon
2)[Z
0+(0.005~0.25Z
0L)]<0.5Z
0L
3I wherein
0---zero-sequence current, 3U
0---residual voltage, I
Mon---zero sequence monitor current, Z
L0---reactor zero sequence impedance, Z
0=---measure zero sequence impedance.
The present invention uses high-speed data acquisition, real-time data signal to handle, and utilizes shunt reactor protection zero sequence impedance criterion and differential, homodyne and protection to constitute the main protection of reactor.Be applicable to 220kV and above shunt reactor, have highly sensitive, quick action, reliability advantages of higher.Concrete method of discrimination is:
By hardware platform, high-side current, low-side current and high terminal voltage that Current Transformer, voltage transformer (VT) are gathered shunt reactor, through mould/number conversion, data processing obtains real-time current, voltage and angle thereof;
With each phase real-time current of gathering, self carry out the week/week relatively, as the current change quantity Δ I of week/week comparison
iGreater than 0.1 reactor secondary rated current I
n, judge that electric system has disturbance, as the distinguishing rule of fault appearance;
The real-time phase current addition of the high-end three-phase of reactor is obtained zero-sequence current 3I
0=(I
1a+ I
1b+ I
1c), I wherein
1a, I
1b, I
1cBe respectively high-end A, B, C three-phase current; The real-time phase voltage addition of high-end three-phase is obtained voltage 3
U0=(U
1a+ U
b+ U
1c), U wherein
1a, U
1b, U
1cBe respectively high-end A, B, C three-phase residual voltage; Again residual voltage, zero-sequence current are divided by and obtain measuring zero sequence impedance Z
0As zero-sequence current 3I
0Greater than zero sequence monitor current I
Mon, and measure zero sequence impedance Z
0Satisfy following formula: [Z
0+ (0.005~0.25Z
0L)]<0.5Z
0L, Z in the formula
0LBe reactor secondary zero sequence impedance, and simultaneously high-side current mutual inductor and voltage transformer (VT) there are not broken string, judge that reactor has turn-to-turn fault or internal interface ground short circuit fault, reactor interturn protection action, respective circuit breakers is jumped in outlet.
With each mutually high-end real-time current I
1With homophase low side real-time current I
2Vector addition is respectively differed stream I
d, A differs stream and is I
Da=| I
1a+ I
2a|, B differs stream for I
Db=| I
1b+ I
2b|, C differs stream for I
Dc=| I
1c+ I
2c|, when arbitrary stream that differs greater than differential action current definite value I
Op, and high-end and low-side current mutual inductor judges that promptly there is fault in reactor when not having broken string, the action of reactor differential protection, and respective circuit breakers is jumped in outlet;
As reactor zero sequence difference current 3I
D.0=(I
1a+ I
1b+ I
1c)+(I
2a+ I
2b+ I
2c) value greater than reactor zero sequence difference current I
Op.0, and high-end and low-side current mutual inductor judges that promptly there is fault in reactor when not having broken string, reactor homodyne protection action, and respective circuit breakers is jumped in outlet.
Reactor back-up protection method of discrimination comprises overcurrent protection, zero sequence overcurrent protection, overload protection method of discrimination: the overcurrent protection method of discrimination: when high-end arbitrary phase phase current continues greater than the overcurrent protection definite value, then judge the reactor overcurrent, respective circuit breakers is jumped in outlet; Zero sequence overcurrent protection method of discrimination: as high-end zero-sequence current 3I
0Continue then to judge reactor zero sequence overcurrent greater than zero sequence overcurrent protection definite value, respective circuit breakers is jumped in outlet; Overload protection method of discrimination:, send out alarm signal when high-end arbitrary phase phase current continues then to judge the reactor overload greater than the overload protection definite value;
The reactor TA method of discrimination that breaks: arbitrary phase current is less than 0.15 times of reactor secondary rated current I in high-end, each phase phase current of low side
n, judge the zero-sequence current situation again, as electric current less than 0.15 times of reactor secondary rated current I
nA side (high-end or low side) zero-sequence current 3I
0Greater than 0.2I
nAnd the zero-sequence current 3I of offside
0Less than 0.2I
n, the reactor difference flows I simultaneously
dLess than 1.2I
nThe time, then be judged as broken string, send out alarm signal, the turn-to-turn of locking simultaneously, differential, homodyne protection;
The reactor TV method of discrimination that breaks: as high-end residual voltage 3U
0Greater than 8V, and the no current sudden change, promptly declare the TV broken string, send out alarm signal, the interturn protection of locking simultaneously; When high-end three-phase phase voltage maximal value less than 30V, and high-end three-phase maximum phase current is greater than 0.1A, promptly declares the TV broken string, sends out alarm signal, the interturn protection of locking simultaneously.
Advantage of the present invention is to adopt method of discrimination of the present invention can reach following performance index:
1, high sensitivity: interturn protection is action message when 1.7% shorted-turn fault.
2, high reliability: a whole set of protective device antijamming capability is strong, stable and reliable operation, and can escape the various transient state processes of system.
3, rapidity: differential and interturn protection action is not more than 25ms.Interturn protection need not escape system's transient state process by time-delay.
4, adjust simply, the protection setting valve only needs input reactance device primary parameter, is generated automatically by software and respectively protects concrete definite value.
Specific implementation method
The invention will be further described below in conjunction with drawings and Examples.
Embodiment, shown in Figure 6.
Shunt reactor interturn short circuit protection zero sequence impedance method of discrimination of the present invention is specifically implemented as follows: with advanced, reliable hardware platform; (its theory diagram is seen Fig. 6) Current Transformer, voltage transformer (VT) are gathered shunt reactor, high-side current, low-side current and high terminal voltage; through mould/number conversion, data processing obtains real-time current, voltage and angle thereof.
With each phase real-time current of gathering, self carry out the week/week relatively, as the current change quantity Δ I of week/week comparison
iGreater than 0.1 reactor secondary rated current I
n, think that promptly electric system has disturbance, as the distinguishing rule of fault appearance.
The real-time phase current addition of the high-end three-phase of reactor is obtained zero-sequence current 3I
0=(I
1a+ I
1b+ I
1c) (I
1a, I
1b, I
1cBe high-end A, B, C three-phase zero-sequence current), the real-time phase voltage addition of high-end three-phase obtains residual voltage 3U
0=(U
1a+ U
b+ U
1c) (U
1a, U
1b, U
1cBe high-end A, B, C three-phase residual voltage), by residual voltage, zero-sequence current is divided by and obtains measuring zero sequence impedance Z
0, Z
0=.As zero-sequence current 3I
0Greater than zero sequence monitor current I
Mon, and measure zero sequence impedance Z
0Satisfy following formula: [Z
0+ (0.005~0.25Z
0L)]<0.5Z
0LThe time (Z in the formula
0LBe reactor secondary zero sequence impedance (definite value).) and simultaneously high-side current mutual inductor and voltage transformer (VT) do not have broken string, judge that promptly reactor has turn-to-turn fault or internal interface ground short circuit fault, reactor interturn protection action, respective circuit breakers is jumped in outlet.
The present invention also can increase reactor differential protection, homodyne protection and back-up protection again and constitute a whole complete reactor protection when implementing.
A, differential protection
With each mutually high-end real-time current I
1With homophase low side real-time current I
2Vector addition is respectively differed stream I
d, I
Da=| I
1a+ I
2a|, I
Db=| I
1b+ I
2b|, I
Dc=| I
1c+ I
2c|, when still one differing stream greater than differential action current definite value I
Op, and high-end and low-side current mutual inductor judges that promptly there is fault in reactor when not having broken string, the action of reactor differential protection, and respective circuit breakers is jumped in outlet.
B, homodyne protection
As reactor zero sequence difference current 3I
D.0Greater than reactor zero sequence difference current, I
Op.0And when high-end and low-side current mutual inductor does not have broken string, judge that promptly there is fault in reactor, reactor homodyne protection action, respective circuit breakers is jumped in outlet.3I wherein
D.0=(I
1a+ I
1b+ I
1c)+(I
2a+ I
2b+ I
2c).
I
1a, I
1b, I
1cBe the high-end A of reactor, B, the real-time phase current of C three-phase;
I
2a, I
2b, I
2cBe reactor low side A, B, the real-time phase current of C three-phase.
C, reactor back-up protection
In the reactor back-up protection, comprise overcurrent protection, zero sequence overcurrent protection, overload protection.
1. overcurrent protection: when high-end arbitrary phase phase current greater than overcurrent protection definite value and lasting regular hour, then judge the reactor overcurrent, respective circuit breakers is jumped in outlet.
2. zero sequence overcurrent protection: as high-end zero-sequence current 3I
0Greater than zero sequence overcurrent protection definite value and lasting regular hour, then judge reactor zero sequence overcurrent, respective circuit breakers is jumped in outlet.
3. overload protection:: when high-end arbitrary phase phase current greater than overload protection definite value and lasting regular hour, then judge the reactor overload, send out alarm signal.
D, the reactor TA differentiation of breaking
Alarm signal is sent out in the differentiation of current transformer loop situation when being used for reactor and normally moving when unusual circumstance, and the turn-to-turn of locking simultaneously, differential, homodyne protection make it not cause misoperation because of the unusual condition misinterpretation reactor fault of current transformer.
It is concrete judge as follows: arbitrary phase current is less than 0.15 times of reactor secondary rated current I in high-end, each phase phase current of low side
n, judge the zero-sequence current situation again, as electric current less than 0.15 times of reactor secondary rated current I
nA side (high-end or low side) zero-sequence current 3I
0Greater than 0.2I
nAnd the zero-sequence current 3I of offside
0Less than 0.2I
nThe reactor difference flows I simultaneously
dLess than 1.2I
n
E, the reactor TV criterion that breaks
Alarm signal is sent out in the differentiation of voltage transformer circuit situation when being used for reactor and normally moving when unusual circumstance, and the turn-to-turn of locking simultaneously makes it not cause misoperation because of the unusual condition misinterpretation reactor fault of voltage transformer (VT).
Its concrete judgement is as follows:
First kind of situation: as high-end residual voltage 3U
0Greater than 20V, and the no current sudden change, promptly declare the TV broken string;
Second kind of situation: when high-end three-phase phase voltage maximal value less than 30V and high-end three-phase maximum phase current greater than 0.1A, promptly declare the TV broken string;
The action parameter that is adopted in above-mentioned criterion can obtain by calculating power system operation mode by the electric system personnel; also can will convert the reactor secondary automatically to according to these parameters by the reactor protection device and respectively protect definite value by the nameplate parameter of input reactance device and relevant device.Be about to TV no-load voltage ratio (n
v), resistance value (Z of principal reactance device
s), resistance value (Z of little reactor
n), rated current (I of principal reactance
N.s), rated current (I of little reactor
N.n) input reactance device protective device, produce corresponding reactance protection parameter automatically by device.
At typical electric system shunt reactor group SR as shown in Figure 1, the high-end serial connection current transformer of three-phase 1TA links to each other with the circuit three-phase with 2K through isolation switch, ground connection behind the serial connection neutral point arc NR after the low side serial connection current transformer 2TA parallel three phase.K1 is the circuit isolation switch, and 1DL is a line-breaker.1TV is that voltage transformer (VT) is parallel on the circuit.
1, gather shunt reactor high-side current mutual inductor TA1, low-side current mutual inductor TA2 and high-end voltage transformer (VT) voltage, through mould/number conversion, Fourier transform obtains real-time current, voltage and angle thereof.
2, each the phase real-time current that will gather, self carry out the week/week relatively, as the current change quantity Δ I of week/week comparison
iGreater than 0.1 reactor secondary rated current I
n, think that promptly electric system has disturbance, as the distinguishing rule of fault appearance.Increasing the zero sequence amount in addition starts as preventing that the difference of phase currents Starting mode may lose restarting ability under situations such as evolved fault, many circuit successive failures and little turn-to-turn fault, as replenishing of difference of phase currents Starting mode.Guarantee that protection all can enter fault handling under the why barrier situation in office.
3, the real-time phase current addition of the high-end three-phase of reactor is obtained zero-sequence current 3I
0=(I
1a+ I
1b+ I
1c) (I
1a, I
1b, I
1cBe high-end ABC three-phase zero-sequence current), the real-time phase voltage addition of high-end three-phase obtains residual voltage 3U
0=(U
1a+ U
b+ U
1c) (U
1a, U
1b, U
1cBe high-end ABC three-phase residual voltage), by residual voltage, zero-sequence current is divided by and obtains measuring zero sequence impedance Z
0, Z
0=.As zero-sequence current 3I
0Greater than zero sequence monitor current I
Mon, and measure zero sequence impedance Z0 and satisfy following formula: [Z
0+ (0.005~0.25Z
0L)]<0.5Z
0LThe time (Z in the formula
0LBe reactor secondary zero sequence impedance (definite value).) and simultaneously high-side current mutual inductor and voltage transformer (VT) do not have broken string, judge that promptly reactor has turn-to-turn fault or internal interface ground short circuit fault, reactor interturn protection action, respective circuit breakers is jumped in outlet.
4, the high-end real-time current I of Jiang Gexiang
1With homophase low side real-time current I
2Vector addition is respectively differed stream I
d,---I
Da=| I
1a+ I
2a|, I
Db=| I
1b+ I
2b|, I
Dc=| I
1c+ I
2c|, when still one differing stream greater than differential action current definite value I
Op, and high-end and low-side current mutual inductor judges that promptly there is fault in reactor when not having broken string, the action of reactor differential protection, and respective circuit breakers is jumped in outlet.
5, as reactor zero sequence difference current 3I
D.0Greater than reactor zero sequence difference current, I
Op.0And when high-end and low-side current mutual inductor does not have broken string, judge that promptly there is fault in reactor, reactor homodyne protection action, respective circuit breakers is jumped in outlet.3I wherein
D.0=(I
1a+ I
1b+ I
1c)+(I
2a+ I
2b+ I
2c).
I
1a, I
1b, I
1cBe the high-end A of reactor, B, the real-time phase current of C three-phase;
I
2a, I
2b, I
2cBe reactor low side A, B, the real-time phase current of C three-phase.
6, reactor back-up protection
1. overcurrent protection: when high-end arbitrary phase phase current greater than overcurrent protection definite value and lasting regular hour, then judge the reactor overcurrent, respective circuit breakers is jumped in outlet.
2. zero sequence overcurrent protection: as high-end zero-sequence current 3I
0Greater than zero sequence overcurrent protection definite value and lasting regular hour, then judge reactor zero sequence overcurrent, respective circuit breakers is jumped in outlet.
3. overload protection:: when high-end arbitrary phase phase current greater than overload protection definite value and lasting regular hour, then judge the reactor overload, send out alarm signal.
7, reactor TA broken string is differentiated
Arbitrary phase current is less than 0.15 times of reactor secondary rated current I in high-end, each phase phase current of low side
n, judge the zero-sequence current situation again, as electric current less than 0.15 times of reactor secondary rated current I
nA side (high-end or low side) zero-sequence current 3I
0Greater than 0.2I
nAnd the zero-sequence current 3I of offside
0Less than 0.2I
nThe reactor difference flows I simultaneously
dLess than 1.2I
nSend out alarm signal, the turn-to-turn of locking simultaneously, differential, homodyne protection make it not cause misoperation because of the unusual condition misinterpretation reactor fault of current transformer.
8, reactor TV broken string criterion
Reactor protection TV breaks in two kinds of situation:
1. first kind of situation: as high-end residual voltage 3U
0In 8~30V, and the no current sudden change, promptly declare the TV broken string; Send out alarm signal, the turn-to-turn of locking simultaneously makes it not cause misoperation because of the unusual condition misinterpretation reactor fault of voltage transformer (VT).
2. second kind of situation: when high-end three-phase phase voltage maximal value less than 30V and high-end three-phase maximum phase current greater than 0.1A, promptly declare the TV broken string; Send out alarm signal, the turn-to-turn of locking simultaneously makes it not cause misoperation because of the unusual condition misinterpretation reactor fault of voltage transformer (VT).
Utilize the reactor protection device collection of the present invention technology differential, homodyne, interturn protection and back-up protection and one, realize that a table apparatus finishes all defencive functions of shunt reactor.And the reactor protection device adopts by user's input reactance device primary parameter, generates the technology of respectively protecting concrete definite value automatically by software, has improved the correctness that device is adjusted greatly.