Definite method of test parameter of winding and sleeve of power transformer
Technical field
The present invention relates to a kind of implementation method of large and medium-sized power transformer High-Voltage Experimentation Technology, especially relate to and utilize variable-frequency power sources to carry out " induced voltage and measurement of partial discharge when winding and sleeve of power transformer is long " method for determining test parameter.
Background technology
By regulation; Large and medium-sized power transformer is after preceding, the overhaul of putting into operation and behind the insulation fault; For whether check transformer primary element exists insulation defect; Whether dielectric level meets the requirement of regulation and producer's technical conditions of related standards, must carry out winding and sleeve induced voltage and measurement of partial discharge when long, finds the defective of transformer manufacturing, installation and maintenance technology timely and effectively.
Because when induced voltage and measurement of partial discharge, existing real component also has idle component to large and medium-sized power transformer, and existing capacitive component in the idle component, perceptual weight is also arranged, but idle component totally demonstrates capacitive component when winding and sleeve is long.
Along with reaching its maturity of Power Electronic Technique, induced voltage and measurement of partial discharge adopted converter plant as experiment power supply more and more widely when the winding and sleeve of power transformer was long.Advantages such as variable-frequency power sources has that starting current is little, the rate of rise is fast, do not have mechanical moving component, self partial discharge quantity is little, but its power is less, the most approximately 500kVA.Generally, the frequency conversion experiment power supply all must adopt reactor to carry out the compensation of capacitive reactive power, and nonetheless, to the test of super-huge, superhigh tension power transformer the time, if parameter matching is unreasonable, the variable-frequency power sources output power can not meet the demands.
Constitute the test loop by large and medium-sized power transformer (test specimen), testing transformer, compensation reactor, experiment power supply, voltage divider unit etc.; Make total comparatively complicated; Particularly under test condition, differed from operating condition by the examination transformer; Frequency, voltage, three-phase symmetry neither with, cause its real component, perceptual idle component, capacitive reactive power component to change, physical model is difficult for setting up; Test parameterss such as basic electric current by each parts in the experience estimation loop, voltage, frequency, test parameters and actual amount often have big large deviation.
Generally, connect test apparatus and test specimen by testing crew after, the examination up voltage if test parameters has than large deviation with estimated value, has to stop test, must the adjustment testing equipment, repeated multiple times like this.Since GB50150-2006 " electric device installation work electrical equipment commissioning test standard " to winding and sleeve of power transformer when long induced voltage and measurement of partial discharge be divided into I, II, III, IV, 5 time periods of V and carry out; The pressing time in each stage and magnitude of voltage all have very strict requirement; 5 pressure periods closely link to each other, necessary disposable completion, and the centre must not be interrupted; The adjustment testing equipment; Will cause by the examination transformer by pressurization repeatedly, bear the high voltage that not should bear and long pressing time, reduce its dielectric level.Because I, II, III, IV, V 5 stages apply voltage, frequency has nothing in common with each other; There is not direct derivation relation in each time period parameter; And have than big-difference, can not use the derive parameter of next time of the parameter of last pressing time of section, though at one time in the section change of a certain parameter will cause the rapid variation of all parameters; Several nothings of adjustment maybe in the on-the-spot short time; Particularly when the III section, will reach the highest trial voltage (the superhigh tension power transformer trial voltage is about 540kV), the longest 60s of time, the shortest only 24s.At this moment; If there is not the accurate Calculation parameter, the test operation personnel cannot observe a plurality of table meters at all simultaneously under high-strung situation; Adjust testing equipment again; The harm that excessive parameter error brings will be directly to damage to be worth millions of units and to be and the voltage transformer of tens million of units, and the accident that high-potting is damaged transformer often has generation, widely influence send out, transmission of electricity.
Summary of the invention
In order to overcome the above-mentioned shortcoming of prior art; The invention provides a kind of definite method of test parameter of winding and sleeve of power transformer, when winding and sleeve is long, before induced voltage and the measurement of partial discharge test, can accurately calculate each test parameters in advance; Testing crew, is only operated by this method established data when carrying out as required in test; And needn't adjust testing equipment repeatedly, each pressure period comprises that the pilot process between the stage accomplishs without any letup, and electric capacity idle component and inductance idle component offset all the time; Be in best compensating coefficient by the examination transformer always; The electric current that only is real component improves the serviceable life of variable-frequency power sources through variable-frequency power sources, and super-huge, superhigh tension power transformer test is carried out in available frequency conversion.
The technical solution adopted for the present invention to solve the technical problems is: a kind of definite method of test parameter of winding and sleeve of power transformer comprises the steps:
The first step, collect, like electric pressure, connect group, each winding over the ground and each other electric capacity, open circuit loss value etc. by examination power transformer technical data;
Second step, utilization are derived and are tried the capacitive reactive power and the lagging reactive power of transformer by the technical data of examination power transformer:
A, use integration by parts,, calculate the capacitive reactive power component of high pressure winding the distributed electrical capacity and the voltage step integration of high pressure winding:
Middle capacitive reactive power component of pressing winding:
The capacitive reactive power component of low pressure winding:
All idle components are converted to the capacitive reactive power component of low pressure winding: Q
Electric capacity=Q
High pressure+ Q
The middle pressure+ Q
Low pressure
B, with the parabolic curve fitting process draw by the examination transformer silicon steel sheet the magnetization curve formula, be converted to the lagging reactive power of each pressure period;
The 3rd goes on foot, confirms each pressure period testing requirements value, selects the mode of connection of testing equipment;
The 4th step, foundation are tried transformer and testing equipment physical model: under the mode of connection of confirming; Will be by the capacitive reactive power of examination transformer; Lagging reactive power; Parameter integrations such as the power that the power that the lagging reactive power of compensation reactor, step-up transformer provide, efficient, gear, variable-frequency power sources provide, efficient are in same equivalent electrical circuit;
The 5th step, set up computer model: utilize ATPdraw software, physical model is integrated in the equivalent electrical circuit obtain by examination characteristic of transformer parameter, measurement voltage divider lumped parameter electric capacity is idle, step-up transformer characteristic parameter and variable-frequency power sources characteristic parameter are plotted in the template of ATPdraw software based on physical model;
The 6th step, basis be the principle Q of reactive power compensation fully
Electric capacity=Q
Inductance+ Q
Compensation, calculate each process " optimum frequency ";
The 7th step, utilization " optimum frequency " calculate each time period real component;
The 8th step, convert each component test parameterss such as into actual " electric current ", " voltage ", " power ", " efficient ", make each variable trend graph.
Compared with prior art; Good effect of the present invention is: the data that the present invention obtains when utilizing design of transformer, manufacturing, conventional test; Adopt integration by parts; To be arrived low-pressure side by the electric capacity distribution and the method reduction of voltage distribution integration by each winding of examination transformer, draw the capacitive reactive power component; Consider that perception is idle to the negative function of the asexual component of capacitive and the variation of each trystate real component under each trystate; Set up the physical model that matches with actual conditions; The final computer model that forms; Induced voltage and measurement of partial discharge each pressure period of test in the time of can precomputing range transformer winding and sleeve length; The voltage of high-tension testing apparatus and test specimen various piece point, electric current, frequency, meritorious, reactive power and component are made each variable trend graph, and the error range of calculated value and actual value is controlled in 1%.For test provides actual standard, avoid maloperation and violation operation, ensure the safety of testing equipment and quilt examination transformer.
The present invention has overcome the blindness that the traditional experiment parameter relies on the experimental formula of personal experience and no physics meaning to estimate; Time, voltage and measurement continuity in the time of satisfying the carrying out that GB50150-2006 " electric device installation work electrical equipment commissioning test standard " requires " Transformer Winding is induced voltage and measurement of partial discharge during together with the cover pipe range "; Calculation method of parameters when utilizing variable-frequency power sources to carry out " Transformer Winding is induced voltage and measurement of partial discharge during together with the cover pipe range " based on physical model and computer model establishment a kind of general is applicable to 110kV and above all types of power transformer.
Embodiment
Disclosed all characteristics in this instructions, or the step in disclosed all methods or the process except mutually exclusive characteristic and/or the step, all can make up by any way.
Disclosed arbitrary characteristic in this instructions (comprising any accessory claim, summary and accompanying drawing) is only if special narration all can be replaced by other equivalences or the alternative features with similar purpose.That is, only if special narration, each characteristic is an example in a series of equivalences or the similar characteristics.
A kind of definite method of test parameter of winding and sleeve of power transformer comprises the steps:
The first step, collect, like electric pressure, connect group, each winding over the ground and each other electric capacity, open circuit loss value etc. by examination power transformer technical data;
Second step, utilization are derived and are tried the capacitive reactive power and the lagging reactive power of transformer by the technical data of examination power transformer:
A, use integration by parts,, calculate the capacitive reactive power component of high pressure winding the distributed electrical capacity and the voltage step integration of high pressure winding:
Simplify promptly
In like manner,
Again because U
Test phase study voltage=2U
Non-test phase study voltage,
So
In like manner, the capacitive reactive power component of middle pressure winding:
The capacitive reactive power component of low pressure winding:
All idle components are converted to the capacitive reactive power component of low pressure winding, promptly
Q
Electric capacity=Q
High pressure+ Q
The middle pressure+ Q
Low pressure
B, with the parabolic curve fitting process draw by the examination transformer silicon steel sheet the magnetization curve formula, be converted to the lagging reactive power of each pressure period:
Because curve is the decision of siliconized plate characteristic, the siliconized plate of different steel mills, the different trades mark has different magnetization curves, so each magnetization curve all need carry out match.Concrete grammar is: limited a plurality of numerical value on the trade-off curve, carry out parabolic interpolation with the QBasic written program, and just can obtain the fitting formula of curve easily, the interpolation point on the trade-off curve is many more, and the formula that obtains is accurate more.
Convert by following formula, obtain the lagging reactive power of each pressure period:
wherein,
I
By the no-load current under the examination transformer rated voltageAnd P
By examination transformer nominal lossIn the test figure of routine property, obtain; For example, under 1.5 trial voltages,
The 3rd goes on foot, confirms each pressure period testing requirements value, selects the mode of connection of testing equipment;
The 4th step, foundation are tried transformer and testing equipment physical model:
Under the mode of connection of confirming; Will be by the capacitive reactive power of examination transformer, lagging reactive power, the lagging reactive power of compensation reactor; Parameter integrations such as the power that the power that step-up transformer provides, efficient, gear, variable-frequency power sources provide, efficient are in same equivalent electrical circuit;
The 5th step, set up computer model: utilize ATPdraw software (world electrician association provides disclosed, free circuit software for calculation), physical model is integrated in the equivalent electrical circuit obtain by examination characteristic of transformer parameter, measurement voltage divider lumped parameter electric capacity is idle, step-up transformer characteristic parameter and variable-frequency power sources characteristic parameter are plotted in the template of ATPdraw software based on physical model;
The 6th step, the principle of pressing complete reactive power compensation calculate each process " optimum frequency ":
Under the different tests state; Frequency changes, and " optimum frequency " is meant provided by variable-frequency power sources one group frequency that changes, through change frequency make by the vector of examination transformer, compensation reactor lagging reactive power and; All the time equal to be tried transformer, measure voltage divider the capacity reactive power vector and; Variable-frequency power sources also only provides active power all the time like this, the minimum of exerting oneself, just " optimum frequency " of whole equivalent electrical circuit.The principle of " optimum frequency " is Q
Electric capacity=Q
Inductance+ Q
Compensation, promptly
" optimum frequency "
in the following formula wherein
is also relevant with
, and the magnetization curve fitting formula through siliconized plate obtains a variable.For this equation of higher order, to utilize ATPdraw software frequency to carry out test run and calculate, the frequency step maximum should be made as 0.1Hz;
The 7th step, utilization " optimum frequency " calculate each time period real component, and concrete computing method are: P
Meritorious=P
The test phase+ 2P
Non-test phase
In like manner,
Wherein k is by the multiple of examination transformer test voltage and rating operating voltage, P
By the specified active loss of examination transformerCan in by examination Transformer Plant Test data, find;
The 8th step, convert each component test parameterss such as into actual " electric current ", " voltage ", " power ", " efficient ", make each variable trend graph:
A, known to each pressure period lagging reactive power of examination transformer, capacitive reactive power, frequency, trial voltage just can obtain test current;
B, known pressure period compensation reactor inductance value, voltage, frequency just can calculate test current;
C, known step-up transformer gear, the voltage of pressure period, frequency just can calculate test current, efficient;
D, the output of known variable-frequency power sources only provide active power under " optimum frequency "; Variable-frequency power sources output voltage, electric current equate with step-up transformer low-pressure side input voltage, electric current, just can calculate variable-frequency power sources output power, efficient and required input three-phase current size.
The present invention is not limited to aforesaid embodiment.The present invention expands to any new feature or any new combination that discloses in this manual, and the arbitrary new method that discloses or step or any new combination of process.