Background technology
Gas-insulated switchgear device has at home and abroad obtained more and more widely using because floor area is little, reliability is high, be subjected to external environment influence little, and shock resistance reaches advantages such as easy to maintenance by force.It is to be connected by the metal contact of seal flange with the inner conductive bar such as power equipments such as isolating switch, disconnector, grounding switch, TA (current transformer), TV (voltage transformer (VT)), buses that gas-insulated switchgear device is formed structure, be sealed in the closed metal cavity of the sulfur hexafluoride gas that is filled with certain pressure, because sulfur hexafluoride gas good insulation performance performance, therefore compare open type transformer station, whole gas-insulated switchgear device physical dimension can be done lessly, but simultaneously the manufacturing and the packaging technology of whole device is also had higher requirement.
Mostly domestic gas-insulated switchgear device equipment is to sue for peace in the eighties in 20th century and begins to drop into operation of power networks the beginning of the nineties, 20 years have nearly been moved at present, to the stage occurred frequently of an accident, have constantly when about the declaration of an accident of gas-insulated switchgear device also being recent years, therefore align insulating property that the gas-insulated switchgear device that is in operation is not equipped with and follow the tracks of detection and be necessary, the principal element that influences this apparatus insulated performance has: the water cut of sulfur hexafluoride gas, the inside of insulated support or surface imperfection, in the manufacture process or the free metal particulate of generation in service, the burr projection of electrode surface, because the legacy that causes in floating potential that screw is loosening or loose contact causes and the installation process etc.The topmost tendency performance of these potential defectives is exactly a shelf depreciation.Therefore detected gas insulated switch shelf depreciation can be found the insulation defect that it is inner early stage, and these early defects are taken appropriate measures, and can avoid the grid power blackout that is caused by the gas-insulated switchgear device accident.
Because gas-insulated switchgear device structurally is totally enclosed, directly detect its failure symptom that may occur internally and realize trouble technically, and must be on production link, directly some sensor or other pick-up units to be installed in gas-insulated switchgear device inside in gas-insulated switchgear device producer, these pick-up units itself just may be one of reasons that causes fault sometimes, and therefore domestic and international most of producer and gas-insulated switchgear device user generally do not wish to adopt built-in online detection mode.
Therefore, prior art can't and be located its shelf depreciation from the gas-insulated switchgear device external detection, gives early detection, locatees its built-in electrical insulation defective and take corresponding measure to cause difficulty.
Summary of the invention
Technical matters to be solved by this invention provides that a kind of sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge detects, positioning system, with from the gas-insulated switchgear device external detection, locate its insulation defect.
For solving the problems of the technologies described above, sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge of the present invention detects, positioning system, comprising: be used for being arranged on the disc insulator outer rim of gas-insulated switchgear device the ultra-high frequency signal receiver, be used to be arranged on ultrasonic receiver and central control unit on the gas-insulated switchgear device outer wall; Central control unit receives continuously from the ultra-high frequency signal of ultra-high frequency signal receiver and the ultrasound wave of ultrasonic receiver, and judges whether described ultra-high frequency signal and ultrasound wave continue to exist correlativity; Described correlativity is meant: the amplitude of ultra-high frequency signal, time, phase characteristic collection of illustrative plates and hyperacoustic amplitude, time, phase characteristic collection of illustrative plates are corresponding; If described ultra-high frequency signal and ultrasound wave continue to exist correlativity, the detection position of then repeatedly mobile ultrasonic receiver on the gas-insulated switchgear device outer wall, and write down appearance maximum amplitude in the amplitude Characteristics collection of illustrative plates of the ultra-high frequency signal on each detection position and the mistiming of the appearance maximum amplitude in hyperacoustic amplitude Characteristics collection of illustrative plates is a time delay, go out the spacing of point of discharge and each detection position then according to each time-delay calculation, and calculate the position of the insulation defect in the gas-insulated switchgear device according to the physical dimension of each detection position and insulated switch; If described ultra-high frequency signal and ultrasound wave continue not exist correlativity, but have a plurality of different phase characteristic collection of illustrative plates, then judge to have a plurality of insulation defects in the gas-insulated switchgear device; Then, by mobile ultrasonic receiver repeatedly on the gas-insulated switchgear device outer wall the detection position and write down corresponding ultrasonic signal intensity and amplitude Characteristics, determine the zone at each the insulation defect place in the gas-insulated switchgear device at last.
As another kind of technical scheme, the square formation that 16 ultra-high frequency signal receivers is constituted 4 * 4 array elements receives battle array to constitute ultrahigh frequency, the square formation that 64 ultrasonic receivers is constituted 8 * 8 array elements receives battle array to constitute ultrasound wave, array element distance in the ultrahigh frequency reception battle array equates and is 2-5m, array element distance in the ultrasound wave reception battle array equates and is 0.2m, and ultrasound wave receives battle array and places ultrahigh frequency to receive battle array and constitute a flat surface sensor, and ultrasound wave receives the central point that battle array and ultrahigh frequency receive gust and overlaps; Central control unit receives the detected local discharge superhigh frequency electromagnetic wave signal of battle array as time reference with ultrahigh frequency, draw the time delay of the ultrasonic signal that each ultrasonic receiver receives, and then calculate the spacing of point of discharge and each ultrasonic receiver, and calculate the position of the insulation defect in the gas-insulated switchgear device according to the physical dimension of the position of each ultrasonic receiver and insulated switch.
Further, described ultra-high frequency signal receiver comprises: ultra-high frequency signal sensor, the prime amplifier that links to each other with the signal output part of ultra-high frequency signal sensor, the frequency mixer that links to each other with the signal output part of prime amplifier, the frequency synthesizer that links to each other with the local oscillation signal end of frequency mixer, the signal amplifier that links to each other with the medium frequency output end of frequency mixer, the low-pass filter that links to each other with the output terminal of signal amplifier, the detection logarithmic amplifier that links to each other with the signal output part of low-pass filter and the data collecting card that links to each other with the signal output part of detection logarithmic amplifier; The output terminal of data collecting card links to each other with the ultra-high frequency signal input end of central control unit, is in series with overvoltage protector between the signal output part of ultra-high frequency signal sensor and the ground wire.
Further, described ultra-high frequency signal sensor comprises: the rectangular metal paster of pasting up and down, the dielectric-slab and the metal base plate of polystyrene material successively; Be connected with the coaxial probe feeding interface on the rectangular metal paster, signal is drawn to described prime amplifier by 50 Ω coaxial radio frequency cables; Described dielectric-slab is a wedge shape.
Further, any two sides of the bottom of described metal base plate and ultra-high frequency signal sensor are provided with metal shield materials (being generally conductive rubber), can wrap disc insulator along two sides, prevent that undesired signal from entering sensor.
The present invention has positive effect: in (1) sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge detection of the present invention, the positioning system, a lot of disc insulators are arranged on the gas-insulated switchgear device usually, the external insulated part of disc insulator is generally poured with epoxy resin spare and teflon etc., and the frequency electromagnetic waves that shelf depreciation produced can penetrate them easily and be radiated outside.The frequency electromagnetic waves that the inner shelf depreciation of gas-insulated switchgear device excites (300M~when 3GHz) propagating through disc insulator, it is external to be radiated gas-insulated switchgear device by epoxy resin etc., shelf depreciation also produces ultrasonic signal simultaneously, ultrasound wave is decayed very fast in gas, but then decay is little in metal.Longer owing to hyperacoustic wavelength simultaneously, so its directivity is stronger, energy is more concentrated.By receiving this acoustical signal, by diagnosing out to the analysis and judgement of acoustical signal whether shelf depreciation has taken place attached to the sonac on the shell.
(2) ultrasound wave is received battle array and place ultrahigh frequency to receive in the battle array, and make their center coincide with same point, purpose is to make point of discharge consistent with the elevation angle to the position angle of the phased reception front scanning of ultrahigh frequency and ultrasound wave, calculates and handles so that simplify.
(3) measurement of partial discharge only is concerned about the peak value of signal and the phase place of appearance thereof usually, ultra-high frequency signal is collected also undistortedly have little significance, and data volume is very big data processing difficulty height.Therefore, must handle signal, the feasible signal of a certain centre frequency of the certain bandwidth of gating hyper band arbitrarily, signal is adjusted to the treatable frequency range of general data capture card, and keep features such as its peak value and phase place, reaching can detection signal, avoids disturbing, and reduces the purpose of technical requirement again.Ultra-high frequency signal receiver based on frequency mixing technique of the present invention just can be realized this function.From application point, the frequency of discharge signal is fallen lowly more, just can reduce equipment manufacturing cost greatly, yet, consider that ultra-high frequency signal is fainter, the bandwidth of acquired signal is too narrow, frequency is just fallen lowly more, and the useful information amount that comprises is just few more, and it is bigger to analyze difficulty; Otherwise, though increased the quantity of information of detection signal, be easy to introduce the communication undesired signal, therefore, choosing of frequency reducing is that process range, signal bandwidth and external interference with common capture card interrelates, and frequency should be reduced to about 40MHz from comprehensive consideration.Simultaneously, frequency mixing technique is actually the envelope that extracts required frequency band signals, and it has kept the peak value and the phase characteristic of former discharge signal ultrahigh frequency component, but can not restore original signal fully, therefore should not adopt multistage mixing, adopts the one-level mixing comparatively suitable.
(4) the ultra-high frequency signal sensor that adopts of the present invention has adopted external UHF microstrip antenna sensor, and it sticks on the back side by the rectangular metal paster has and form on the dielectric-slab of conductor ground plate.This sensor utilizes the slit between metal patch and the metal base plate to receive uhf electromagnetic wave, and be converted into high-frequency current, carry out feed with coaxial probe as feeder line, and the coaxial radio frequency cable by 50 Ω is transferred to prime amplifier in the ultra-high frequency signal receiver to signal.This sensor is installed in the disc insulator outer rim place in the gas-insulated switchgear device, receives from the uhf electromagnetic wave of disc insulator to external leakage, and the surrounding space electromagnetic interference (EMI) is had good inhibitory effect.Its effective working band is 400-1200MHz (standing-wave ratio (SWR)<2), reached all channel antenna scope, and the gain on greatest irradiation and the receive direction has reached 5.38dBi.Wherein, dielectric-slab is selected the lower polystyrene material of specific inductive capacity for use, and its specific inductive capacity is 2.62.
The bandwidth of ultra-high frequency signal sensor can represent with the percentage of the ratio of centre frequency with the high-end frequency and the difference of low side frequency, promptly
In the formula: f
0Be centre frequency.The pulse energy of shelf depreciation almost is directly proportional with frequency span, and the narrow-band characteristic of ultra-high frequency signal sensor is to have the resonance person's character of its high Q to determine, the energy that promptly is stored in the ultra-high frequency signal sensor construction is more much bigger than radiation and other energy loss, realized coupling when this means resonance, and the reactive component drastic change makes it mismatch during frequency departure resonance.Total quality factor q of ultra-high frequency signal sensor is:
In the formula: Q
r, Q
cAnd Q
dRepresent respectively by radiation power Pr, the caused corresponding Q value of conductor losses power P c, dielectric loss power P d.In order to obtain more shelf depreciation information, should widening frequency band when design.The method of widening frequency band can go to seek from the various aspects that reduce total Q value, also can realize with additional coupling measure.The present invention adopts following method to carry out widening frequency band: (a) adopt the less substrate of DIELECTRIC CONSTANT r: medium substrate has been selected the lower polystyrene material of specific inductive capacity for use, purpose is to reduce ε r, the energy storage of antenna because of ε r reduce diminish, thereby frequency band is broadened.(b) adopt thick substrate: the increase radiation conductance of thickness also increases thereupon, and the Q of radiation correspondence and total Q value reduce, and make frequency band widen.(c) select wedge-shaped substrate for use: in identical feed position, the standing-wave ratio (SWR) of wedge-shaped medium substrate resonator is wide more a lot of than common rectangle less than 2 frequency band.Experiment shows that this method of employing can be with about one times of electric band spread, and this substrate shape changes makes the reason of electric band spread be: because two different resonators of two radiation port substrate thickness cause through the two-circuit phenomenon that the ladder capacitive coupling produces.(d) adopt the additional impedance matching network: the equivalent electrical circuit of ultra-high frequency signal sensor can be described with a RLC antiresonant circuit, under back of the body feedback situation, feed probes can be considered a reactance, add a series capacitance this moment, form the resonant circuit of connecting with the antenna probe inductance, and make it and ultra-high frequency signal sensor equivalent antiresonant circuit at same frequency upper resonance, near the reactance of series parallel resonance loop resonance frequency is tending towards offsetting, the rapid variation of reactance when having made it to avoid off-resonance, thus broadening frequency band.Adopt and select antenna substrate material, thickness and methods such as shape, additional impedance matching network to carry out electric band spread, the working band 400-1200MHz of the microstrip antenna after the electric band spread, standing-wave ratio (SWR)<2, centre frequency is 390MHz, relative bandwidth 25.6 reaches all channel antenna scope; Show that in laboratory and built-in annulus sensor contrast test the ultra-high frequency signal sensor has higher sensitivity, the actual measurement gain has reached 5.38dB, helps the detection of faint local discharge signal; Structurally, the design of metal material barrier enclosure is adopted in the back side and the part side of ultra-high frequency signal sensor, improved the antijamming capability of ultra-high frequency signal sensor.Bottom and part side to the ultra-high frequency signal sensor shield, and make the ultra-high frequency signal sensor have directivity, make the uhf electromagnetic wave of reception obtain maximum gain, and make the undesired signal gain of coupling from the side less.The bracing frame that the ultra-high frequency signal sensor is made by epoxy resin is fixed on the disc insulator flange.
Embodiment
(embodiment 1)
See Fig. 1-4, the sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge of present embodiment detects, positioning system comprises: the ultra-high frequency signal receiver of outer rim 9 that is used for being arranged on the disc insulator 7 of gas-insulated switchgear device, be used to be arranged on the gas-insulated switchgear device outer wall 6 ultrasonic receiver, central control unit 1, and the display 2 that links to each other with central control unit 1, the GPRS3 that is used to provide wireless telecommunications that links to each other with central control unit 1, what link to each other with central control unit 1 is used for LAN (Local Area Network) communication unit 4 with remote monitoring center 5 communications.Disc insulator 7 is enclosed within on the inner wire 8 of gas-insulated switchgear device.
Central control unit 1 receives continuously from the ultra-high frequency signal of ultra-high frequency signal receiver and the ultrasound wave of ultrasonic receiver, and judges whether described ultra-high frequency signal and ultrasound wave continue to exist correlativity; Described correlativity is meant: the amplitude of ultra-high frequency signal, phase characteristic collection of illustrative plates and hyperacoustic amplitude, phase characteristic collection of illustrative plates are corresponding; If described ultra-high frequency signal and ultrasound wave continue to exist correlativity, the detection position of then repeatedly mobile ultrasonic receiver on the gas-insulated switchgear device outer wall, and write down appearance maximum amplitude in the amplitude Characteristics collection of illustrative plates of the ultra-high frequency signal on each detection position and the mistiming of the appearance maximum amplitude in hyperacoustic amplitude Characteristics collection of illustrative plates is a time delay, go out the spacing of point of discharge and each detection position then according to each time-delay calculation, and calculate the position of the insulation defect in the gas-insulated switchgear device according to the physical dimension of each detection position and insulated switch.
If described ultra-high frequency signal and ultrasound wave continue not exist correlativity, but have a plurality of different phase characteristic collection of illustrative plates, then judge to have a plurality of insulation defects in the gas-insulated switchgear device; Then, by mobile ultrasonic receiver repeatedly on the gas-insulated switchgear device outer wall the detection position and write down corresponding ultrasonic signal intensity and amplitude Characteristics, determine the zone at each the insulation defect place in the gas-insulated switchgear device at last.
The shelf depreciation spectrogram that with the phase place is variable has reflected the distribution by phase place in power frequency period of discharge capacity and number of times, the phase window that the phase place of 0~360 degree is divided into some, observe the Characteristics of Partial Discharge in each phase window, thereby form a complete shelf depreciation spectrogram that comprises all phase places.
Described ultra-high frequency signal receiver comprises: ultra-high frequency signal sensor UHF, the prime amplifier 10 that links to each other with the signal output part of ultra-high frequency signal sensor UHF, the frequency mixer 11 that links to each other with the signal output part of prime amplifier 10, the frequency synthesizer 16 that links to each other with the local oscillation signal end of frequency mixer 11, the signal amplifier 12 that links to each other with the medium frequency output end of frequency mixer 11, the low-pass filter 13 that links to each other with the output terminal of signal amplifier 12, the detection logarithmic amplifier 14 that links to each other with the signal output part of low-pass filter 13, and the data collecting card 15 that links to each other with the signal output part of detection logarithmic amplifier 14; The output terminal of data collecting card 15 links to each other with the ultra-high frequency signal input end of central control unit 1, is in series with overvoltage protector 17 between the signal output part of ultra-high frequency signal sensor UHF and the ground wire.
Described ultra-high frequency signal sensor UHF comprises: rectangular metal paster A, the dielectric-slab B and the metal base plate C of polystyrene material that pastes up and down successively; Be connected with coaxial probe feeding interface D on the rectangular metal paster A, signal is drawn to described prime amplifier 10 by 50 Ω coaxial radio frequency cables; Described dielectric-slab B is a wedge shape.
Any two sides of the bottom of described metal base plate C and ultra-high frequency signal sensor UHF are provided with metal shield materials.
The ultra-high frequency signal receiver transforms to intermediate frequency with the frequency of input signal or the carrier frequency of modulated signal in the presence of local oscillation signal, and keeps keeping features such as its peak value and phase place, and this frequency conversion process is called mixing.
Wherein: overvoltage protector 17 can prevent that the transient state high-energy from damaging signal condition unit and data collecting card.Prime amplifier 10, be used to guarantee discharge signal through after the long-distance transmissions during arriving signal conditioning unit power magnitude of signal meet its input range.The frequency band range of the broadband amplifiers that system is used is 0-800MHz, the working band of covering system.Frequency mixer 11 mainly plays the frequency reducing effect, promptly exports the difference frequency signal of local oscillation signal and input signal.The local oscillator input range of the frequency mixer of selecting for use in the system is 20MHz-1.5GHz, and the intermediate frequency output area is DC-1GHz, and dynamic range is 60dB.Frequency synthesizer 16, major function are to produce the local oscillation signal that meets the demands, by program control this unit of computer parallel interface, the centre frequency of scalable acquired signal thus.The centre frequency scope that this system is adjustable is 400-1200MHz, and minimum step is 25MHz.Signal amplifier 12 amplifies the intermediate-freuqncy signal of frequency mixer output, satisfies the needs of subsequent treatment.Low-pass filter 13, its effect be after the filtering mixing and frequency component, output difference frequency component.System design 7 rank Chebyshev LC low-pass filters.Can change the bandwidth of gating frequency band by the bandwidth that changes low-pass filter, it is optional that bandwidth is set to two kinds of gears of 25MHz, 50MHz, and this operation realizes by parallel port of computing machine.Detection logarithmic amplifier 14 carries out detection (envelope extraction) and amplification to the signal by low-pass filter output.
Through local discharge superhigh frequency signal (centre frequency is between 400-1200MHz, and bandwidth is that 25MHz, 50MHz are optional) behind the mixing conditioning unit but frequency reducing is the signal that is lower than 20MHz, conditioned signal can be sent into capture card at last and carry out data processing.
The application of frequency mixing technique has been equivalent to realize the bandpass filter that bandwidth is optional, centre frequency is adjustable, (centre frequency is between 400-1200MHz with the local discharge superhigh frequency signal for it, bandwidth is that 25MHz, 50MHz are optional) frequency reducing is the signal that is lower than 20MHz, and kept features such as the peak value of signal and phase place.Can extract the ultra high frequency discharge signal of gas-insulated switchgear device typical case shelf depreciation model effectively with frequency mixing technique, can calculate the discharge correlation parameter exactly, not only avoided interference but also comprised discharge information as much as possible, on performance and applicability, be more suitable for carrying out the local discharge superhigh frequency on-line monitoring than spectrum analyzer and full range band direct detection method.
(embodiment 2)
On the basis of embodiment 1, the sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge of present embodiment detects, positioning system has following distortion: the square formation that 16 ultra-high frequency signal receivers is constituted 4 * 4 array elements receives battle array to constitute ultrahigh frequency, the square formation that 64 ultrasonic receivers is constituted 8 * 8 array elements receives battle array to constitute ultrasound wave, array element distance in the ultrahigh frequency reception battle array equates and is 2-5m, array element distance in the ultrasound wave reception battle array equates and is 0.2m, and ultrasound wave receives battle array and places ultrahigh frequency to receive battle array and constitute a flat surface sensor, and ultrasound wave receives the central point that battle array and ultrahigh frequency receive gust and overlaps.
Central control unit 1 receives the detected local discharge superhigh frequency electromagnetic wave signal of battle array as time reference with ultrahigh frequency, draw the time delay of the ultrasonic signal that each ultrasonic receiver receives, and then calculate the spacing of point of discharge and each ultrasonic receiver, and calculate the position of the insulation defect in the gas-insulated switchgear device according to the physical dimension of the position of each ultrasonic receiver and insulated switch.
(embodiment 3)
On the basis of embodiment 1 and 2, the sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge of present embodiment detects, positioning system has following distortion:
Consider the narrow band signal (S of D shelf depreciation
1, S
2..., S
D) incide on the linear array of ultrahigh frequency reception battle array, wherein array is made up of M array element, and array element is spaced apart the d (see figure 1).
The array output vector can be expressed as X (t)=A (θ) S (t)+N (t),--(1)
Formula (1) is the mathematical model of arrowband far-field signal, wherein, and A (θ)=[α (θ
1), α (θ
2) ...,
α (θ
N)] be the direction matrix or the array flow pattern of array;
α (θ
i)=[1, e
-j2 π dSin θ i/ λ..., e
-j (M-1) 2 π dSin θ i/ λ]
t, be the direction vector (λ is the wavelength of incoming signal) of incoming signal; S (t) is the incoming signal vector; X (t) is a received signal vector; N (t) is the array noise vector.
Obtain the covariance matrix R of array output vector X (t):
R=E[XX
H]=AE[SS
H]A
H+σ
2I=ARSA
H+σ
2I,
Wherein, R
S=E[S (t) S (t)
H] be signal covariance matrix, σ
2I=E[n (t) n (t)
H].A
HConjugate transpose for A; σ
2Be noise power; N (t) is a noise sequence.
Because it is separate that A respectively is listed as, and mutual when uncorrelated at incoming signal, R
SBe nonsingular matrix, so:
Rank(AR
SA
H)=D。
Because of R
SBe positively definite matrix, matrix A R then
SA
HBe nonnegative definite, total D positive eigenwert and M-D zero eigenvalue [19,20].Again because of σ 2>0, AR
SA
HNonnegative definite, R is the full rank battle array, so R has M real positive eigenwert.R is carried out feature decomposition:
Wherein, λ
1, λ
2..., λ
MThe eigenwert of expression R, and eigenwert carried out descending sort, then have:
λ
1>λ
2...λ
D>λ
D+1=λ
D+2=...=λ
M
Wherein, the D of R big eigenwert characteristic of correspondence vector ∑
S=diag (λ
1, λ
2..., λ
D) the subspace U that opens
S=Span{e
1, e
2..., e
D}=Span{ α (θ
1), α (θ
2) ..., α (θ
D), be called signal subspace.M-D little eigenwert characteristic of correspondence vector ∑
n=diag (λ
D+1, λ
D+2..., λ
M) the subspace U that opened
n=Span{e
D+1, e
D+2..., e
M, be called noise subspace, according to the feature decomposition theory as can be known, U
SAnd U
nMutually orthogonal, that is:
α
H(θ)U
n=0。--(2)
Classical MUSIC algorithm is based on above-mentioned this character proposition, but considers that the actual reception data matrix has the limit for length, and promptly the maximal possibility estimation of R is
Right
Carry out feature decomposition and can calculate the noise subspace eigenvectors matrix
Because of the existence of noise, α (θ) with
Quadrature fully, promptly formula (2) is false.In fact ask direction of arrival to realize, promptly with minimum optimization searching
So Estimation of Spatial Spectrum P of MUSIC algorithm
MUSICFormula is:
The position angle of N the peak value correspondence of angular spectrum P (θ) is exactly the direction of shelf depreciation point.MUSIC algorithm wherein is a multiple signal classification algorithm, be classical Estimation of Spatial Spectrum algorithm, reach the super-resolution spectrum and estimate that the .MUSIC algorithm can finish DOA (direction of arrival) and estimate and Frequency Estimation by acknowledge(ment) signal being divided into noise subspace and signal subspace (this two subspaces quadrature). its essence is noise subspace algorithm based on linear search.