Summary of the invention
The purpose of the invention is to overcome the shortcoming of background technique, and provide a kind of huge water wheel generator group resistance
Anti- parameter automatic optimizing method determines full after the requirement that engineers and technicians propose short circuit current and transient overvoltage
The earthing mode required enough and ground connection parameter configuration section.
To achieve the goals above, the technical scheme is that:Huge water wheel generator group impedance parameter automatic optimal
Method, it is characterised in that:It includes the following steps,
S1:Voltage rating U based on generatorN, the single-phase total capacitance C over the ground of stator winding0, short circuit current safety limit
IsafeAnd resistance R and reactance XLParameter configuration section determination formula, determine resistance R and reactance XLParameter configuration area
Between, it is specific to determine that formula is as follows:
Wherein, formula (4) is suitable for tandem type, and formula (5) is suitable for parallel connection type, UNFor the voltage rating of generator, C0For
The single-phase total capacitance over the ground of stator winding, ω are angular frequency, and j is imaginary unit, IsafeFor short circuit current limit value, UsafeFor transient state mistake
Voltage limits, R are resistance, XLFor reactance;
S2:The resistance R and reactance X determined according to formula (4)LParameter configuration section, draw resistance R and reactance XLPass
It is curve;
S3:On the corresponding resistance of above-mentioned steps S2 and reactance curve, and according to the undercompensation section of inductance value, in [XS0,
+ ∞) in interval range, find so that transient overvoltage Up is the numerical point of 2.6pu, at this time determining RS、XSIt is as corresponding to match
Set parameter;
Wherein, the undercompensation section of inductance value is:
S4:The resistance R and reactance X determined according to formula (5)LParameter configuration section, draw resistance R and reactance XLPass
It is curve;
S5:On the corresponding resistance of above-mentioned S4 and reactance curve, and according to the undercompensation section of inductance value, in [XP0,+∞)
In interval range, find so that transient overvoltage Up is the numerical point of 2.6pu, the R determined at this timeP、XPAs corresponding configuration ginseng
Number;
Wherein, the undercompensation section of inductance value is:
S6:Combination technology economy and technical feasibility, and according to final resistance R and reactance XLIt is grounded parameter installation group
Close cabinet style impedance type generator neutral point earthing or grounding means.
The present invention provides a kind of combination cabinet style impedance type generator neutral point earthing or grounding means, compared with prior art,
It has the following advantages that:
1, it is easily installed and safeguards, armamentarium is placed in a cabinet body by traditional neutral earthing devices, this
Although arrangement can save spatial position to a certain extent, single cabinet body volume is big, weight weight, and installation and maintenance are not
Convenient, after combination cabinet body, single cabinet body splits into 3 cabinet bodies, and single cabinet body is small in size, light-weight, it is more easy to install and
Maintenance, is also convenient for replacing.
2, electric link mode and parameter configuration can be with flexible choices.
3, when power plant capacity-increasing transformation or other need to change the situation of grounding transformer or resistor or reactance value etc. when,
Equipment in single equipment cabinet can be transformed or be replaced, transformation is more flexible, is easier.
4, the electric operating of disconnecting switch may be implemented in the introducing of motor-operating mechanism, and satisfaction needs to carry out earthing or grounding means
The requirement electrically switched.
Specific embodiment
The performance that the invention will now be described in detail with reference to the accompanying drawings, but they and do not constitute a limitation of the invention, only
It is for example.Keep advantages of the present invention more clear by explanation simultaneously and is readily appreciated that.
Refering to known to attached drawing:Huge water wheel generator group impedance parameter automatic optimizing method, includes the following steps,
S1:Voltage rating U based on generatorN, the single-phase total capacitance C over the ground of stator winding0, short circuit current safety limit
IsafeAnd resistance R and reactance XLParameter configuration section determination formula, determine resistance R and reactance XLParameter configuration area
Between, it is specific to determine that formula is as follows:
Wherein, formula (1) is suitable for tandem type, and formula (2) is suitable for parallel connection type, UNFor the voltage rating of generator, C0For
The single-phase total capacitance over the ground of stator winding, ω are angular frequency, and j is imaginary unit, IsafeFor short circuit current limit value, UsafeFor transient state mistake
Voltage limits, R are resistance, XLFor reactance;
S2:The resistance R and reactance X determined according to formula (1)LParameter configuration section, draw resistance R and reactance XLPass
It is curve;
S3:On (rather than in value interval) the corresponding resistance of above-mentioned steps S2 and reactance curve, and according to inductance value
Undercompensation section, in [XS0,+∞) in interval range, finds so that transient overvoltage Up is the numerical point of 2.6pu, determine at this time
Series resistance RSWith series inductance XSAs corresponding configuration parameter;
Wherein, the undercompensation section of inductance value is:
S4:The resistance R and reactance X determined according to formula (2)LParameter configuration section, draw resistance R and reactance XLPass
It is curve;
S5:On (rather than in value interval) the corresponding resistance of above-mentioned S4 and reactance curve, and according to the underfill of inductance value
Section is repaid, in [XP0,+∞) in interval range, find so that transient overvoltage Up is the numerical point of 2.6pu, it is determining at this time and
Join resistance RpWith shunt inductance XpAs corresponding configuration parameter;
Wherein, the undercompensation section of inductance value is:
S6:Combination technology economy and technical feasibility, and according to final resistance R and reactance XLIt is grounded parameter installation group
Close cabinet style impedance type generator neutral point earthing or grounding means.
In actual work, combination cabinet style impedance type gigantic generating units neutral earthing devices, including resistor cabinet 1,
Transformer case 2 and reactor cabinet 3;
Wherein, the resistor cabinet 1 and reactor cabinet 3 are located at the secondary side or ipsilateral of transformer case 2, when resistor cabinet 1
With reactor cabinet 3 be series connection be coupled when, transformer case 2 input terminal access resistor cabinet 1 input terminal, resistor cabinet 1 it is defeated
Outlet is coupled with the input terminal of reactor cabinet 3, the output end of reactor cabinet 3 and the output coupled of transformer case 2;Work as resistor
When cabinet 1 and reactor cabinet 3 are in parallel be coupled, the input terminal of the input terminal access resistor 12 of transformer case 2, while accessing electricity
The input terminal of anti-device cabinet 3;
Wherein, the inductance X on the resistance R and reactor cabinet 3 on resistor cabinet 1LFollowing formula should be met:
Wherein, formula (1) is suitable for resistor cabinet 1 and the series connection of reactor cabinet 3 is coupled, and formula (2) is suitable for resistor cabinet
1 and reactor cabinet 3 is in parallel is coupled, UNFor the voltage rating of generator, C0For the single-phase total capacitance over the ground of stator winding, ω is angular frequency
Rate, j are imaginary unit, IsafeFor short circuit current limit value, UsafeFor transient overvoltage limit value, R is resistance, XLFor reactance, vlimFor
The limit value of tuning-off degree as defined in fire protection technology;
The transformer case 2 includes transformation shell 21, transformation bracket 22, the switch operation machine above transformation bracket 22
Structure 4, the transformation mechanism 5 positioned at 22 lower section of transformation bracket;
The transformation bracket 22, switch operating mechanism 4 and transformation mechanism 5 are installed in inside transformation shell 21;
The switch operating mechanism 4 includes the first transformation block 41, the second transformation block 42, the first support insulator 43, second
Support insulator 44, switch tool 45, switch driver 46, switch driving handle 47, switch transmission corner block 48, described first
Transformation block 41 and the second transformation block 42 are installed on transformation bracket 22, and the first support insulator 43 is mounted on the first transformation block 41
On, the second support insulator 44 is mounted on the second transformation block 42, described 45 one end of switch tool and the first support insulator 43
Connection, the other end are connect with the second support insulator 44, and described 46 one end of switch driver is connect with switch tool 45, the other end
It is connect with the end of switch transmission corner block 48, the middle part of the switch transmission corner block 48 and the first transformation block 41 are hinged, institute
It states switch driving handle 47 to be mounted on the first transformation block 41, and switchs the output end and switch transmission corner block of driving handle 47
48 middle part connects and switch transmission corner block 48 is driven to rotate;
The transformation mechanism 5 includes transformation upper yoke 51 and transformation lower yoke 52, and 52 lower end of transformation lower yoke passes through transformation
Supporting block is installed on 21 bottom end of transformation shell, spaced apart transformer winding 53 there are two installations on transformation lower yoke 52, and two
A transformer winding 53 is connect with transformation upper yoke 51, and is connected between two transformer windings 53 by winding coupling line 54
It connects, transformation copper bar 55 is also equipped on the winding coupling line 54, transformation copper bar 55 passes through transformation insulated column and transformation shell 21
Inner sidewall connection;
The resistor cabinet 1 includes resistance shell 11 and resistor 12, is sequentially connected from top to bottom inside resistance shell 11
Have first resistor support frame 13, second resistance support frame 14 and resistance partition 15, be equipped on the resistor 12 resistor into
Line 16 and several resistance copper bars 17, and 12 upper end of resistor is connected by the side wall of first resistor insulator 18 and resistance shell 11
It connects, 12 lower end of resistor is connect by second resistance insulator 19 with first resistor support frame 13, the first resistor support frame
13 lower ends are connected with resistance mesh enclosure 110, and the first current transformer 111, second electricity are equipped on second resistance support frame 14
It is that reserved resistance holds matter space 112 between resistance support frame 14 and resistance partition 15;
The reactor cabinet 3 includes reactance shell 31 and reactor 32, inside the reactance shell 31 from top to bottom successively
It is connected with the first reactance support frame 33, the second reactance support frame 34 and reactance partition 35, reactance is installed on the reactor 32
Device inlet wire 36, and 32 upper end of reactor is connect by the first reactance insulator 37 with the side wall of reactance shell 31, under reactor 32
End is connect by the second reactance insulator 38 with the first reactance support frame 33, and 33 lower end of the first reactance support frame is connected with electricity
Anti- mesh enclosure 39 is equipped with the second current transformer 310, the second reactance support frame 34 and reactance on second reactance support frame 34
It is that matter space 311 is held in reserved reactance between partition 35;
It is respectively connected with outside 11 outside of resistance shell and reactance shell 31 and shutter 61 and ground wire entrance 62 is installed,
Cold dew device 63 and electric heater terminal 64 are mounted on the resistance partition 15 and reactance partition 35.
In actual work, the ground side method for arranging of huge water wheel generator group includes the following steps,
Step 1:Neutral ground scheme and device parameter are first determined by owner, design side and equipment producer,
Then according to the scheme determined, the equipment arrangement of turbine-generator units is carried out in workshop generator floor;
Step 2:Input the voltage rating U of generatorN, the single-phase total capacitance C over the ground of stator winding0, short circuit current limit value
IsafeWith transient overvoltage limit value Usafe, judge whether generator needs to be grounded, be if desired grounded, then neutral ground dress is installed
It sets, if not needing to be grounded, neutral earthing devices is not installed, wherein the decision condition whether generator is grounded includes single-phase
Whether earth current is more than whether permissible value and generator capacity are greater than 125MW;
Step 3:When determining that generator need to be grounded, criterion is related to according to power industry and judges whether that moment is required to cut machine,
If it is desired to which moment cuts machine, then using high reactance type earthing mode (through grounding through arc, the external common prior art), if not
It is required that moment cuts machine, then enter next step, that is, further determines selection impedance type earthing mode or high-ohmic type
Earthing mode;It should be noted that in the case where not requiring moment to cut machine, it can also be (external common using " high reactance " type
The prior art), but it needs to consider the factors such as neutral point displacement voltage, and the Overvoltage Amplitude relative to other two ways is inclined
Height, therefore the present invention does not recommend;
Step 4:According to the natural capacity electric current I of generatorc, compare natural capacity electric current IcWith short circuit current IsafeLimit
Value, ifThen consider high-ohmic type earthing mode, this is the prior art, and specific resistance value configuration method can be according to NB/
T 35067-2015《Hydraulic power plant's overvoltage protection and Insulation Coordination designing technique directive/guide》;IfThen consider impedance
Type earthing mode, into next step;
Step 5:According to the limit value of short circuit current and resistance R and reactance XLParameter configuration section determination formula,
Determine resistance R and reactance XLParameter configuration section, meanwhile, according to transient overvoltage limit value UsafeAnd the undercompensation of inductance value
Section determines final resistance R and reactance XLIt is grounded parameter configuration mode;
Wherein, resistance R and reactance XLParameter configuration section determination formula it is as follows:
The undercompensation section of inductance value is:
Wherein, formula (1) is suitable for tandem type, and formula (2) is suitable for parallel connection type, UNFor the voltage rating of generator, C0For
The single-phase total capacitance over the ground of stator winding, ω are angular frequency, and j is imaginary unit, IsafeFor short circuit current limit value, UsafeFor transient state mistake
Voltage limits, R are resistance, XLFor reactance, vlimFor the limit value of tuning-off degree as defined in fire protection technology;
Step 6:Final grounding scheme configuration parameter is exported, and according to final resistance R and reactance XLIt is grounded parameter
Installation combination cabinet style impedance type generator neutral point earthing or grounding means.
Present invention mainly solves two impedance configuration patterns, impedance parameter equipping rules key technical problems, thus just
In engineers and technicians quickly, reliably carry out System Parameter Design.
1. impedance configuration pattern
Generator neutral point through impedance earth, refer to the corresponding substitutional resistance of neutral ground circuit and reactance be not 0 or
It can not ignore, when traditional high resistance ground through distribution transformer, although there are certain inductance values for transformer, relative to resistance
Value, inductance value are negligible;Similarly for the mode through grounding through arc, although arc suppression coil there are certain resistance value,
But its resistance value very little is negligible.
When resistance and reactance value be can not ignore, resistance and reactance, which can connect, connection or in parallel is coupled two kinds of forms;
Further, since impedance transformation can be carried out by distribution transformer, therefore resistance and reactance can be connected to distribution separately or together
Circuit Fault on Secondary Transformer, therefore impedance configuration pattern one shares 8 kinds, as shown in Fig. 5 to 12.
The selection of above-mentioned 8 kinds of modes, need to be after the final impedance ground parameter of determination, bonding apparatus space layout, distribution
The various aspects such as transformer parameter, technical solution economy are comprehensively considered.As shown in Fig. 5 to 12, the present invention is only provided not
With the equivalent equipping rules to impedance parameter after distribution transformer primary side of connection type, i.e., the different equal abbreviations of connection type are
Tandem type of the Fig. 5 into Fig. 8, Fig. 9 two kinds of patterns of the parallel connection type into Figure 12.
2. impedance parameter equipping rules
(1) short circuit current in single phase grounding
The electric current I of Single-phase Ground Connection FailureKIncluding two parts:
1) natural capacity electric current IC
In formula, UNFor rated voltage;ω is angular frequency, Rad/s;C0It is single-phase right for generator unit stator voltage circuit
Ground total capacitance;J is imaginary unit.
2) neutral point zero-sequence current In
In formula, UNFor rated voltage;ZnFor generator neutral point earth impedance, it is assumed that the earthing mode of proposed adoption
Equivalent impedance is Zn=RS+jXS(series connection) or Zn=RP//jXP(parallel connection), in formula, j is imaginary unit, RSElectricity when to connect
Resistance, XSInductance when to connect, RPResistance when for parallel connection, XPInductance when in parallel.
The expression formula of total short circuit current is:
After determining short circuit current safety limit, the parameter of resistance and reactance under different connection forms, i.e. RS、XS
Or RP、XP(RSResistance when to connect, XSInductance when to connect, RPResistance when for parallel connection), XPInductance when in parallel is controlled
System is specifically detailed in Fig. 6 and Fig. 7 in certain range etc.
Its specific rule is:
A, the resistance R when resistance and reactance series connection are coupled, when series connectionS, series connection when inductance XSParameter configuration range be
In the interval range surrounded for curve in Figure 13 and reference axis, with the reduction of short circuit current limit value, value interval is gradually reduced.
B, the resistance R when resistance and reactance parallel connection are coupled, when series connectionS, series connection when inductance XSParameter configuration range be
In the interval range surrounded for curve in Figure 14 and reference axis, with the reduction of short circuit current limit value, value interval is gradually reduced.
(2) transient overvoltage
Standard regulation need to be by transient overvoltage amplitude limit value within the scope of 2.6pu, and transient overvoltage there is no clearly at present
The changing rule of analytical expression, transient overvoltage provided by the invention is as follows:
A, when resistance and reactance series connection are coupled, if resistance R when fixed series connectionSValue, then it is corresponding when being 0 with tuning-off degree
XS0Centered on value, [0, XS0) in section, with XSIncrease, transient overvoltage amplitude reduce;In (XS0,+∞) and in range,
With XSIncrease, transient overvoltage amplitude increase.
B, when resistance and reactance series connection are coupled, if inductance X when fixed series connectionSValue, then with RSReduction, transient state mistake
Voltage magnitude increases.
C, when resistance and reactance parallel connection are coupled, if resistance R when in parallelPValue, then corresponding X when being 0 with tuning-off degreeP0
Centered on value, [0, XP0) in section, with XPIncrease, transient overvoltage amplitude reduce;In (XP0,+∞) and in range, with
XPIncrease, transient overvoltage amplitude increase.
When resistance and reactance parallel connection are coupled, if inductance X when fixed in parallelPValue, then with RPIncrease, transient state is excessively electric
Pressure amplitude value increases.
D, only consider from short circuit current and Overvoltage Amplitude angle, under the conditions of identical short circuit current safety limit, and be coupled
Maximum transient overvoltage is slightly less than series connection and is coupled under mode.
(3) auxiliary principle
Based on (1) short circuit current, (2) transient overvoltage principle, and combination technology economy, technical feasibility compare, can
It determines and is grounded parameter configuration used by corresponding huge water wheel unit, auxiliary principle provided by the invention is available for users to further
Clearly it is coupled any of pattern using 8 kinds shown in Fig. 5 to 12.
After determining impedance parameter based on (1) short circuit current, (2) transient overvoltage principle, and the technology warp of optional program
In the case of Ji property, technical feasibility no significant difference, auxiliary principle is as follows:
A, preferential using connecting scheme in parallel;
B, resistance is preferentially placed on to the secondary survey of distribution transformer device;
C, inductance is preferentially placed on to the primary side of distribution transformer;
D, for series connection and parallel connection, in the case that tuning-off degree is 0, transient overvoltage amplitude is minimum, and since impedance type is matched
Set the use of scheme, in conventional method various other transient overvoltages as caused by tuning-off degree is 0 there is no.But due to hair
The insulation margin of motor is typically chosen larger, significantly larger than 2.6pu, and using tuning-off degree is 0 scheme to transient overvoltage
Reduction it is less obvious, be typically 2.5pu or so, therefore do not use tuning-off degree for 0 scheme, it is excessively electric that preferential recommendation meets transient state
The undercompensation parameter configuration under the conditions of limit value is pressed, as shown in Figure 14 and Figure 16.
In actual work, according to transient overvoltage limit value Usafe, using intelligent search algorithm, form final ground connection parameter
Configuration mode.
The concrete principle of intelligent search algorithm is:In determining search range, with certain step-length to the electricity in range
Resistance carries out analytical calculation with reactance value, and Automatic-searching meets the ground connection parameter configuration mode of transient overvoltage limit value requirement, specifically
Ground:First determine the inductance value of arc suppression coil under the conditions of undercompensation for meeting tuning-off degree requirement, the primary election side of integrated ground parameter
Case;Further determine that the range of resistance R;After determining resistance and reactance search range, and then intelligent search algorithm is applied, found
Meet transient overvoltage limit value U in search rangesafeGround connection parameter configuration mode.
Other unaccounted parts belong to the prior art.