CN104319738A - Protection setting calculation model for high-voltage variable-frequency motor - Google Patents

Abstract

The invention discloses a protection setting calculation model for a high-voltage variable-frequency motor. The protection setting calculation model for the high-voltage variable-frequency motor comprises a protection setting calculation model for the high-voltage variable-frequency motor with a phase-shifting transformer and a protection setting calculation model for the high-voltage variable-frequency motor without the phase-shifting transformer, and each of the two protection setting calculation models comprises a long start protection setting calculation model, a current quick-breaking protection setting calculation model, an overcurrent protection setting calculation model, a negative-sequence current protection setting calculation model, an overheat protection setting calculation model, a ground protection setting calculation model and a low-voltage protection setting calculation model; the protection setting calculation model for the high-voltage variable-frequency motor without the phase-shifting transform further comprises a locked-rotor protection setting calculation model. The protection setting calculation model for the high-voltage variable-frequency motor provides reference basis for the protection setting calculation of the high-voltage variable-frequency motor, and therefore, the protection functions are more complete, the protection set value is more reasonable, and the high-voltage frequency converter and the high-voltage motor can be protected to the utmost extent.

Description

A kind of high-pressure frequency-conversion motor protection adaptive setting model

Technical field

The present invention relates to a kind of high-pressure frequency-conversion motor protection adaptive setting model, belong to technical field of relay protection.

Background technology

In recent years, due to the impact by load configuration change, the peak-valley difference of electrical network is increasing.A lot of generating set for this reason, even the unit of Large Copacity, high parameter all will participate in peaking operation.Peak regulation task makes the opening of high pressure auxiliary motor, stops number of times and increase frequently, and motor causes the situation cumulative year after year of insulation damages because being hit; On the other hand, the way of employing regulating fender, valve opening carries out output variable adjustment, causes subsidiary engine long-time running in inefficient service area, causes energy waste serious.In order to improve the running environment of motor, simultaneously in order to reduce station service power consumption rate, " in Eleventh-Five Year Plan ten large emphasis energy conservation project implementation guidelines " propose to promote variable-frequency control technique, and emphasis carries out speed governing transformation to big-and-middle-sized variable working condition electric system.At present, the Important Auxiliary equipment of most power plant, as blower fan, water pump etc., generally all adopts frequency converter to drag.After frequency converter, conventional motors protection can not be satisfied the demand and the fail safe of motor is on the hazard.Research and analysis are carried out to the protection problem of motor in frequency conversion system; then adaptive setting optimization is carried out targetedly; proposing more perfect, more rational synchronizing calculation method, is important topic urgently to be resolved hurrily in the practical process of current Medium Voltage Variable Frequency Speed Regulation Technology.

The article of the domestic and international Energy Saving Benefit Analysis brought for high voltage converter is a lot of at present; but it is relatively less for the Protective strategy of adjusting after high-tension motor frequency conversion; and a lot of article just proposes general setting method, but for really can to apply in practice and the adaptive setting of solving practical problems is discussed seldom.After motor attached with frequency converters, very large impact is created on the traditional protection mode of motor.Current high-pressure frequency-conversion motor protection configuration is not enough, needs the relaying configuration scheme studying new applicable wide region frequency modulation high-tension motor.

Summary of the invention

The object of the present invention is to provide a kind of high-pressure frequency-conversion motor protection adaptive setting model, provide reference frame can to high-pressure frequency-conversion motor protection adaptive setting.

For achieving the above object, the technical solution adopted in the present invention is: a kind of high-pressure frequency-conversion motor protection adaptive setting model, comprise band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model and be not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, described band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model and be not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model to include: long starting protection adaptive setting model, current quick adaptive setting model, overcurrent protection adaptive setting model, unbalanced fault protection adaptive setting model, Over Heat Protection Setting Calculation model, ground protection adaptive setting model and under-voltage protection adaptive setting model, described phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model of not being with also comprises rotation-clogging protection adaptive setting model.

Described long starting protection adaptive setting model is:

The specified starting current I of (a) motor _st

I _st＝K _stI _e

In formula, for band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, I _efor phase shifting transformer secondary rated current, K _stfor safety factor; For not being with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, I _efor motor secondary rated current, K _stfor resetting ratio; K _stget 1.2;

B () motor is under converting operation mode, start-up time, proper extension, considered to leave nargin, if be t start-up time _op

t _op＝(1.2-1.3)t _qd

In formula, t _qdfor the motor start-up time of power frequency actual measurement.

The current quick adaptive setting model of described band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model comprises: vacuum circuit-breaker current quick adaptive setting model and FC loop current fast tripping protection adaptive setting model, and FC loop current fast tripping protection adaptive setting model comprises again: adaptive setting model and the adaptive setting model having big current locking tripping operation outlet function without big current locking tripping operation outlet function:

A, vacuum circuit-breaker current quick adaptive setting model

(1) operating current: adjust by the magnetizing inrush current escaping phase shifting transformer, namely

I _oph＝KI _e

In formula: K is multiple, depending on transformer capacity, the concrete span of K is as follows:

6300kVA and following: 7 ~ 12;

6300kVA～31500kVA：4.5～7.0；

40000kVA～120000kVA：3.0～6.0；

120000kVA and more than: 2.0 ~ 5.0;

(2) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{k.\min }^{\left(2\right)}}{I_{\mathrm{oph}}{n}_{\mathrm{TA}}}\≥2$

In formula: n _tAfor the high-voltage switch gear inlet wire no-load voltage ratio that protection uses;

for in protection zone, high-pressure side, line to line fault flows through on high-tension side electric current;

I _ophfor current quick operating current;

(3) action delay: for the mode all adopting vacuum circuit-breaker, get 0.05s;

B, FC loop current fast tripping protection adaptive setting model:

A, without big current locking tripping operation outlet function adaptive setting model, as follows:

(1) operating current: identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, that is: I _oph=KI _e;

(2) action delay: t _opget the maximum duration of fuse fuse failure, span is: 0.3 ~ 1s.

B, big current locking is had to trip the adaptive setting model of outlet function, as follows:

(1) operating current: identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, that is: I _oph=KI _e;

(2) latching current definite value I _art

$20I_{\mathrm{TA}.n}\≥I_{\mathrm{art}}=\frac{I_{\mathrm{brk}}}{K_{\mathrm{rel}}{n}_{\mathrm{TA}}}$

In formula: I _artfor big current locking definite value;

I _brkfor vacuum contactor allows turn-off current;

K _relfor safety factor, get 1.3 ~ 1.5;

(3) action delay

t _op＝0.05～1s

(4) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{\mathrm{art}}}{I_{\mathrm{oph}}}\≥2.$

The described current quick adaptive setting model not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model also comprises: vacuum circuit-breaker current quick adaptive setting model and FC loop current fast tripping protection adaptive setting model; FC loop current fast tripping protection adaptive setting model comprises again: adaptive setting model and the adaptive setting model having big current locking tripping operation outlet function without big current locking tripping operation outlet function: C, vacuum circuit-breaker current quick adaptive setting model, as follows:

(2) operating current: adjust by the principle escaping the maximum starting current of motor, namely

I _oph＝K _relK _st·I _e

In formula: K _relfor safety factor gets 1.5;

K _stfor motor starting current multiple, calculate by measured value, span is 6 ~ 8;

(2) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{k.\min }^{\left(2\right)}}{I_{\mathrm{oph}}{n}_{\mathrm{TA}}}\≥2$

In formula: n _tAfor high-voltage switch gear inlet wire no-load voltage ratio;

for motor entrance minimum line to line fault electric current one sub-value;

I _ophfor current quick operating current;

(3) action delay: for the mode all adopting vacuum circuit-breaker, operate time gets 0.05s.

D, FC loop current fast tripping protection adaptive setting model, as follows:

(1) without the adaptive setting of big current locking tripping operation outlet function:

(a) operating current:

Identical with vacuum circuit-breaker current quick-breaking operating current synchronizing calculation method, i.e. I _oph=K _relk _sti _e;

(b) action delay: t _opget the maximum duration of fuse fuse failure, span is: 0.3 ~ 1s;

(2) the adaptive setting model of big current locking tripping operation outlet function is had, as follows:

(a) operating current:

Identical with vacuum circuit-breaker current quick-breaking operating current synchronizing calculation method, i.e. I _oph=K _relk _sti _e;

(b) latching current setting value I _artcalculate

$20I_{\mathrm{TA}.n}\≥I_{\mathrm{art}}=\frac{I_{\mathrm{brk}}}{K_{\mathrm{rel}}{n}_{\mathrm{TA}}}$

In formula: I _artfor big current locking definite value; I _brkfor vacuum contactor allows turn-off current; K _relfor safety factor, get 1.3 ~ 1.5;

(3) action delay:

t _op＝0.05～1s；

(4) sensitivity check:

$K_{\mathrm{sen}}=\frac{I_{\mathrm{art}}}{I_{\mathrm{oph}}}\≥2.$

Described overcurrent protection adaptive setting model is:

(a) operating current

For band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, operating current I _opadjust by escaping phase shifting transformer secondary rated current; For not being with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, operating current I _opadjust by escaping motor secondary rated current;

$I_{\mathrm{op}}=\frac{K_{\mathrm{rel}}}{K_r}{I}_e$

In formula: K _relfor safety factor, get 1.05 ~ 1.2;

K _rfor resetting ratio, get 0.85 ~ 0.95;

(b) action delay

t _op＝(1-1.1)t _qd

In formula: t _opfor overcurrent protection action delay;

T _qdfor the motor start-up time.

Described unbalanced fault protection adaptive setting model comprises: negative phase-sequence I segment protect adaptive setting model and negative phase-sequence II segment protect protection seting computation model:

(a) negative phase-sequence I segment protect adaptive setting model:

By when escaping unsymmetrical short-circuit outside district when motor negative phase-sequence feedback current and motor start-up due to the negative-sequence current that current transformer error and transient characterisitics occur, and ensure that motor has enough sensitivity synthesis to consider to calculate when larger load two-phase operation and motor interior unsymmetrical short-circuit:

Operating current I _2.1dz:

I _2.1dz＝(0.6～1.4)I _e

Action delay t _2.1dz:

1) if device provides negative phase-sequence reverse blocking function, t _2.1dz=(0.5 ~ 1) s;

2) if device does not provide negative phase-sequence reverse blocking function, t _2.1dz=(5 ~ 6) s, the misoperation that the negative-sequence current produced to escape the outside two-phase short-circuit fault of motor causes;

(b) negative phase-sequence II segment protect adaptive setting model:

By escaping maximum negative-sequence current possible when motor normally runs and motor compared with there being enough sensitivity to consider during Smaller load two-phase operation, using as sensitive unbalance protection, can alarm be selected:

Operating current I _2.2dz:

I _2.2dz＝(0.2～0.35)I _e

Action delay t _2.2dz: get the start-up time being greater than motor.

Described Over Heat Protection Setting Calculation model comprises: motor occur overheated time Over Heat Protection Setting Calculation model and based on IEC60255-8 overheated with real index curve rise Over Heat Protection Setting Calculation model;

When () motor occurs overheated a, temperature raises with the initial climbing speed of the exponential curve of reality always, and its model is

${\∫}_0^t[{\left(\frac{I_{\mathrm{eq}}}{I_e}\right)}^2-{1.05}^2]\mathrm{dt}\≥\mathrm{\τ}$

$I_{\mathrm{eq}}^2=K_1{I}_1^2+K_2{I}_2^2$

In formula: I _efor motor secondary rated current;

I _eqfor causing the equivalent current of heating;

τ is electric motor overheating time constant;

I ₁, I ₂for the positive and negative sequence electric current of motor;

K ₁, K ₂for positive and negative sequence heating effect of current coefficient, K in starting process of motor ₁get 0.5 ~ 1, K ₂get 3 ~ 10;

B () is as follows based on the overheated Over Heat Protection Setting Calculation model with the rising of real index curve of IEC60255-8:

${\∫}_0^t\frac{1}{\ln \left(\frac{I_{\mathrm{eq}}^2-\mathrm{\ξ}{I}_{\left[0\right]}^2}{I_{\mathrm{eq}}^2-I_{\∞}^2}\right)}\mathrm{dt}\≥\mathrm{\τ}$

In formula: I _[0]for overheated front motor current;

ξ is a coefficient of considering under motor normal operation to dispel the heat, and gets 50%;

I _∞for overtemperature protection starting current, span is (1.05 ~ 1.15) I _e.

Described ground protection adaptive setting model comprises: isolated neutral system one-phase ground protection adaptive setting model and Neutral Point Through Low Resistance system one-phase ground protection adaptive setting model:

A, isolated neutral system one-phase ground protection adaptive setting model are as follows:

(1) operating current

Calculate by the earth current flowing through protection installation place when escaping single-phase earthing outside district, that is:

$I_{\mathrm{op}.0}{=K}_{\mathrm{rel}}{I}_k^{\left(1\right)}$

In formula: I _op.0for single-phase earthing zero sequence excess current protection act electric current;

K _relfor safety factor, get 2.5 ~ 3s when protection act also trips, protection act gets 2 ~ 2.5s when signal;

for the earth current of protected equipment supply short dot during single-phase earthing outside dorsal zone, i _efor protected equipment positive direction capacitance current sum during single-phase earthing outside dorsal zone;

(2) operate time

When 3 ~ 10kV earth current is not less than 10A, get 0.5 ~ 1s;

When 3 ~ 10kV earth current is less than 10A, to 300MW and above unit, if when meeting selectivity and sensitivity requirement, get 0.5 ~ 1s;

When 3 ~ 10kV earth current is less than 10A, during as sensitivity can not be met and optionally require, can action in signal, get 0.5s;

(3) sensitivity test

$K_{\mathrm{sen}}^{\left(1\right)}=\frac{I_{\mathrm{k\Σ}}^{\left(1\right)}-I_k^{\left(1\right)}}{I_{\mathrm{op}.0}}\≥1.5$

In formula: during for protected equipment generation single-phase earthing, earthing capacitance current two sub-value that fault point is total;

B, Neutral Point Through Low Resistance system one-phase ground protection adaptive setting model are as follows:

(1) operating current: get the greater in both following (a) and (b);

A () calculates by escaping single-phase earthing outside district

$I_{\mathrm{op}.0}=K_{\mathrm{rel}}{I}_k^{\left(1\right)}$

In formula: K _relfor safety factor, get 1.1 ~ 1.15;

B () calculates by escaping busy hour unsymmetrical current

I _op.0＝K _relI _umb

In formula: K _relfor safety factor, get 1.3;

I _umbfor busy hour unsymmetrical current;

I _umb≤ (0.1 ~ 0.15) × I _n, I _nfor feeder line rated current;

(2) action delay: 0 ~ 0.05s;

(3) sensitivity check

$K_{\mathrm{sen}}^{\left(1\right)}=\frac{I_{\mathrm{k\Σ}}^{\left(1\right)}}{I_{\mathrm{op}.0}}\≥2$

In formula: for single-phase earthing of small current earthing system electric current.

Described under-voltage protection adaptive setting model comprises as follows:

(1) for the motor with intermediate system, the operation voltage of low-voltage variation:

U _dz＝(0.6～0.7)U _N

Action delay: 0.5 ~ 1.5s;

(2) for there is the motor automatically dropping into stand-by machine, the operation voltage of under-voltage protection:

U _dz＝(0.4～0.5)U _N

Action delay: 5 ~ 10s.

Described rotation-clogging protection adaptive setting model is as follows:

(1) below 600MW unit:

Operating current: I _dz=(1.3 ~ 1.5) I _e;

Action delay: t _op.set=15 ~ 20s;

(2) the fan-type unit of more than 600MW:

Calculate by escaping sort time overcurrent

Operating current: I _dz=(1.8 ~ 2.0) I _e;

Action delay: t _op.set=15 ~ 20s;

Or

Adjust as operating current setting value: I _dz=1.5I _e;

Action delay: t _op.set=25 ~ 30s;

(3) 600MW is with charging pump class unit:

Operating current: I _dz=(1.3 ~ 1.5) I _e;

Action delay: t _op.set=15 ~ 20s.

Compared with prior art; the beneficial effect that the present invention reaches is: the protection seting computation model providing a kind of high-pressure frequency-conversion motor; reference frame is provided to high-pressure frequency-conversion motor protection adaptive setting; make defencive function more perfect; protection definite value is more reasonable; protect high voltage converter and high-tension motor to greatest extent, significantly reduce the operation expense of thermal power plant.

Embodiment

High-pressure frequency-conversion motor protection adaptive setting model, comprises band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model and is not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model.

Be with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model and be not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model to include: long starting protection adaptive setting model, current quick adaptive setting model, overcurrent protection adaptive setting model, unbalanced fault protection adaptive setting model, Over Heat Protection Setting Calculation model, ground protection adaptive setting model and under-voltage protection adaptive setting model.

Below protection seting computation model each in the present invention is further described, for technical scheme of the present invention is clearly described, and can not limits the scope of the invention with this.

1.1. long starting protection adaptive setting model

(1) the specified starting current I of motor _st

I _st＝K _stI _e

In formula, for band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, I _efor phase shifting transformer secondary rated current, K _stfor safety factor; For not being with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, I _efor motor secondary rated current, K _stfor resetting ratio; K _stgenerally get 1.2.

(2) motor is under converting operation mode, and start-up time, proper extension, considered to leave nargin, if be t start-up time _op

t _op＝(1.2-1.3)t _qd

In formula, t _qdfor the motor start-up time of power frequency actual measurement, namely motor start-up reaches the time of rated speed to rotating speed.When not surveying, desirable: circulating water pump is 20s, electrically driven feed pump is 20s, and forced draft fan is 20s, and induced-draught fan is 20s, and coal pulverizer is 20s, and exhaust blower is 15s, and some other startup is the desirable 10s of motor faster.

1.2. current quick adaptive setting model

Current quick adaptive setting model comprises vacuum circuit-breaker current quick adaptive setting model and FC loop current fast tripping protection adaptive setting model, and FC loop current fast tripping protection adaptive setting model comprises: without adaptive setting model and the adaptive setting model having big current locking tripping operation outlet function of big current locking tripping operation outlet function.For band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, be not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, establish respective current quick adaptive setting model respectively.

In band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, current quick adaptive setting model detailed content is as follows:

1.2.1. vacuum circuit-breaker current quick adaptive setting model

(1) operating current

Adjust by the magnetizing inrush current escaping phase shift transformation and suppress device, namely

I _oph＝KI _e

In formula: K is multiple, depending on transformer capacity, the span of K is as follows:

6300kVA and following: 7 ~ 12;

6300kVA～31500kVA：4.5～7.0；

40000kVA～120000kVA：3.0～6.0；

120000kVA and more than: 2.0 ~ 5.0.

(2) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{k.\min }^{\left(2\right)}}{I_{\mathrm{oph}}{n}_{\mathrm{TA}}}\≥2;$

In formula: n _tAfor (high-voltage switch gear inlet wire) CT no-load voltage ratio that protection uses;

for in protection zone, high-pressure side, line to line fault flows through on high-tension side electric current;

I _ophfor current quick operating current.

(3) action delay

For the mode all adopting vacuum circuit-breaker, operate time gets 0.05s.

1.2.2.FC loop current fast tripping protection adaptive setting model

1.2.2.1 without the adaptive setting model of big current locking tripping operation outlet function:

(1) operating current

Identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, i.e. I _oph=KI _e.

(2) action delay

T _opget the maximum duration of fuse fuse failure, recommend 0.3s ~ 1s.

1.2.2.2 the adaptive setting model of big current locking tripping operation outlet function is had:

(1) operating current

Identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, i.e. I _oph=KI _e.

(2) latching current definite value I _art

$20I_{\mathrm{TA}.n}\≥I_{\mathrm{art}}=\frac{I_{\mathrm{brk}}}{K_{\mathrm{rel}}{n}_{\mathrm{TA}}}$

In formula: I _artfor big current locking definite value;

I _brkfor vacuum contactor allows turn-off current;

K _relfor safety factor, get 1.3 ~ 1.5;

(3) action delay

t _op＝0.05～1s；

(4) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{\mathrm{art}}}{I_{\mathrm{oph}}}\≥2.$

Not as follows with the detailed content of current quick adaptive setting model in phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model:

2.3.1 vacuum circuit-breaker current quick adaptive setting model

(1) operating current

Adjust by the principle escaping the maximum starting current of motor, namely

I _oph＝K _relK _st·I _e

In formula: K _relfor safety factor gets 1.5.K _stfor motor starting current multiple, generally between 6 ~ 8, should calculate by measured value, as got K without actual measurement _st=7.

(2) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{k.\min }^{\left(2\right)}}{I_{\mathrm{oph}}{n}_{\mathrm{TA}}}\≥2$

In formula: n _tAfor CT no-load voltage ratio; for motor entrance minimum line to line fault electric current one sub-value;

I _ophfor current quick operating current.

(3) action delay

For the mode all adopting vacuum circuit-breaker, operate time gets 0.05s.

2.3.2FC loop current fast tripping protection adaptive setting model

(1) without the adaptive setting of big current locking tripping operation outlet function:

(a) operating current

Identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, i.e. I _oph=K _relk _sti _e.

(b) action delay

T _opget the maximum duration of fuse fuse failure, span is 0.3 ~ 1s.

(2) adaptive setting of big current locking tripping operation outlet function is had:

(a) operating current

Identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, i.e. I _oph=K _relk _sti _e.

(b) latching current setting value I _artcalculate

$20I_{\mathrm{TA}.n}\≥I_{\mathrm{art}}=\frac{I_{\mathrm{brk}}}{K_{\mathrm{rel}}{n}_{\mathrm{TA}}}$

In formula: I _artfor big current locking definite value; I _brkfor vacuum contactor allows turn-off current; K _relfor safety factor, get 1.3 ~ 1.5.

(c) action delay:

t _op＝0.05～1s；

(d) sensitivity check:

$K_{\mathrm{sen}}=\frac{I_{\mathrm{art}}}{I_{\mathrm{oph}}}\≥2.$

1.3. overcurrent protection adaptive setting model

(1) operating current

Adjust by escaping the strong secondary rated current of phase shift transformation

$I_{\mathrm{op}}=\frac{K_{\mathrm{rel}}}{K_r}{I}_e$

In formula: K _relfor safety factor, get 1.05 ~ 1.2;

K _rfor resetting ratio, get 0.85 ~ 0.95.

(2) action delay

t _op＝(1-1.1)t _qd

In formula: t _opfor overcurrent protection action delay; t _qdfor the motor start-up time.

1.4. negative phase-sequence overcurrent protection adaptive setting model

Motor turn-to-turn short circuit is done in negative phase-sequence overcurrent protection, disconnected phase, phase sequence are made mistakes, supply power voltage compared with the protection of large unbalance, backup protection effect is play to motor asymmetry short circuit fault.Unbalanced fault protection adaptive setting model comprises: negative phase-sequence I segment protect adaptive setting model and negative phase-sequence II segment protect protection seting computation model.

(1) negative phase-sequence I segment protect adaptive setting model

By when escaping unsymmetrical short-circuit outside district when motor negative phase-sequence feedback current and motor start-up due to the negative-sequence current that current transformer error and transient characterisitics occur, and ensure that motor has enough sensitivity synthesis to consider to calculate when larger load two-phase operation and motor interior unsymmetrical short-circuit.

Operating current I _2.1dz:

I _2.1dz＝(0.6～1.4)I _e

Action delay t _2.1dz:

1) if device provides negative phase-sequence reverse blocking function, t _2.1dz=(0.5 ~ 1) s;

2) if device does not provide negative phase-sequence reverse blocking function, t _2.1dz=(5 ~ 6) s, the misoperation that the negative-sequence current produced to escape the outside two-phase short-circuit fault of motor causes;

(2) negative phase-sequence II segment protect adaptive setting model

By escaping maximum negative-sequence current possible when motor normally runs and motor compared with there being enough sensitivity to consider during Smaller load two-phase operation, using as sensitive unbalance protection, can alarm be selected.

Operating current I _2.2dz:

I _2.2dz＝(0.2～0.35)I _e

Action delay t _2.2dz: generally get the start-up time being greater than motor.

1.5. Over Heat Protection Setting Calculation model

Over Heat Protection Setting Calculation model comprises: motor occur overheated time Over Heat Protection Setting Calculation model and based on IEC60255-8 overheated with real index curve rise Over Heat Protection Setting Calculation model.

Over Heat Protection Setting Calculation model when () motor occurs overheated a: when motor occurs overheated, temperature raises with the initial climbing speed of the exponential curve of reality always, and its model is

${\∫}_0^t[{\left(\frac{I_{\mathrm{eq}}}{I_e}\right)}^2-{1.05}^2]\mathrm{dt}\≥\mathrm{\τ}$

$I_{\mathrm{eq}}^2=K_1{I}_1^2+K_2{I}_2^2$

In formula: I _efor motor secondary rated current;

I _eqfor causing the equivalent current of heating;

τ is electric motor overheating time constant; Should be provided by motor manufactory, as producer does not provide, the stator temperature rise under the capability of overload data that can provide according to producer, locked rotor current and permission stall time, starting current, motor starting current multiple and calculate start-up time.

I ₁, I ₂for the positive and negative sequence electric current of motor;

K ₁, K ₂for positive and negative sequence heating effect of current coefficient, K in starting process of motor ₁get 0.5 ~ 1, negative-sequence current thermal effect COEFFICIENT K ₂get 3 ~ 10, generally desirable 6;

B () is as follows based on the overheated Over Heat Protection Setting Calculation model with the rising of real index curve of IEC60255-8:

${\∫}_0^t\frac{1}{\ln \left(\frac{I_{\mathrm{eq}}^2-\mathrm{\ξ}{I}_{\left[0\right]}^2}{I_{\mathrm{eq}}^2-I_{\∞}^2}\right)}\mathrm{dt}\≥\mathrm{\τ}$

In formula: I _[0]for overheated front motor current, generally equal rated current, if motor overload is in cold standby state, then equal zero;

ξ is a coefficient of considering under motor normal operation to dispel the heat, and gets 50%;

I _∞for overtemperature protection starting current, span is (1.05 ~ 1.15) I _e, general desirable 1.1I _e.

Adaptive setting

(4) heat radiation time constant, desirable 32 ~ 36min, for high power motor, generally gets 4 τ.

1.6. ground protection adaptive setting model

Ground protection adaptive setting model comprises: isolated neutral system one-phase ground protection adaptive setting model and Neutral Point Through Low Resistance system one-phase ground protection adaptive setting model.

1.6.1 isolated neutral system one-phase ground protection adaptive setting model

(1) operating current

Calculate by the earth current flowing through protection installation place when escaping single-phase earthing outside district, that is:

$I_{\mathrm{op}.0}=K_{\mathrm{rel}}{I}_k^{\left(1\right)}$

In formula: I _op.0for single-phase earthing zero sequence excess current protection act electric current;

K _relfor safety factor, get 2.5 ~ 3s when protection act also trips, protection act gets 2 ~ 2.5s when signal.

for the earth current of protected equipment supply short dot during single-phase earthing outside dorsal zone, i _efor protected equipment positive direction capacitance current sum during single-phase earthing outside dorsal zone.

(2) operate time

When 3 ~ 10kV earth current is not less than 10A, get 0.5 ~ 1s.

When 3 ~ 10kV earth current is less than 10A, to 300MW and above unit, if when meeting selectivity and sensitivity requirement, tripping operation is selected in suggestion, and operate time gets 0.5 ~ 1s.

When 3 ~ 10kV earth current is less than 10A, during as sensitivity can not be met and optionally require, can action in signal, operate time gets 0.5s.

(3) sensitivity test

$K_{\mathrm{sen}}^{\left(1\right)}=\frac{I_{\mathrm{k\Σ}}^{\left(1\right)}-I_k^{\left(1\right)}}{I_{\mathrm{op}.0}}\≥1.5$

In formula: during for protected equipment generation single-phase earthing, earthing capacitance current two sub-value that fault point is total;

1.6.2 Neutral Point Through Low Resistance system one-phase ground protection adaptive setting

(1) operating current: get (a) and (b) both the greater.

A () calculates by escaping single-phase earthing outside district

$I_{\mathrm{op}.0}=K_{\mathrm{rel}}{I}_k^{\left(1\right)}$

In formula: K _relfor safety factor, get 1.1 ~ 1.15.

B () calculates (only just considering this principle when not using special zero sequence CT) by escaping busy hour unsymmetrical current

I _op.0＝K _relI _umb

In formula: K _relfor safety factor, get 1.3;

I _umbfor busy hour unsymmetrical current;

Generally: I _umb≤ (0.1 ~ 0.15) × I _n, I _nfor feeder line rated current.

(2) action delay: 0 ~ 0.05s.

(3) sensitivity check

$K_{\mathrm{sen}}^{\left(1\right)}=\frac{I_{\mathrm{k\Σ}}^{\left(1\right)}}{I_{\mathrm{op}.0}}\≥2$

In formula: for single-phase earthing of small current earthing system electric current.

1.7. under-voltage protection adaptive setting model

When supply network voltage reduces, the rotating speed of asynchronous motor all will decline, and when power supply buses voltage recovers, a large amount of motor self-starting, absorbs several-fold starting current large compared with its rated current, causes voltage recovery time to be spun out.For preventing making line voltage seriously reduce for a long time during motor self-starting; usually will install under-voltage protection on secondary motor, when power supply buses voltage is reduced to certain value, secondary motor excises by time delay; power supply buses is made to have enough voltage, to ensure important motor self-starting.Under-voltage protection is divided into two-stage:

(1) for the motor of the coal pulverizer and ash pump, slurry pump, coal crusher etc. that have middle coal bunker pulverized coal preparation system, the operation voltage of under-voltage protection:

U _dz＝(0.6～0.7)U _N

Action delay: 0.5 ~ 1.5s.

(2) for the motor with water supply pump and condensate pump and recirculated water pump motor, forced draft fan and the straight blown converter pulverized coal preparation system coal pulverizer automatically dropping into stand-by machine, the operation voltage of under-voltage protection:

U _dz＝(0.4～0.5)U _N

Action delay: 5 ~ 10s.

1.8. rotation-clogging protection adaptive setting model

Phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model is not with also to comprise rotation-clogging protection adaptive setting model, specific as follows:

(1) below 600MW unit:

Operating current: I _dz=(1.3 ~ 1.5) I _e;

Action delay: t _op.set=15 ~ 20s;

(2) the fan-type unit of more than 600MW:

Calculate by escaping sort time overcurrent

Operating current: I _dz=(1.8 ~ 2.0) I _e;

Action delay: t _op.set=15 ~ 20s;

Or

Adjust as operating current setting value: I _dz=1.5I _e;

Action delay: t _op.set=25 ~ 30s;

(3) 600MW is with charging pump class unit:

Operating current: I _dz=(1.3 ~ 1.5) I _e;

Action delay: t _op.set=15 ~ 20s.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the technology of the present invention principle; can also make some improvement and distortion, these improve and distortion also should be considered as protection scope of the present invention.

Claims (10)

1. a high-pressure frequency-conversion motor protection adaptive setting model, it is characterized in that, comprise band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model and be not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, described band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model and be not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model to include: long starting protection adaptive setting model, current quick adaptive setting model, overcurrent protection adaptive setting model, unbalanced fault protection adaptive setting model, Over Heat Protection Setting Calculation model, ground protection adaptive setting model and under-voltage protection adaptive setting model, described phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model of not being with also comprises rotation-clogging protection adaptive setting model.

2. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1, is characterized in that, described long starting protection adaptive setting model is:

The specified starting current I of (a) motor _st

I _st＝K _stI _e

In formula, for band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, I _efor phase shifting transformer secondary rated current, K _stfor safety factor; For not being with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, I _efor motor secondary rated current, K _stfor resetting ratio; K _stget 1.2;

B () motor is under converting operation mode, start-up time, proper extension, considered to leave nargin, if be t start-up time _op

t _op＝(1.2-1.3)t _qd

In formula, t _qdfor the motor start-up time of power frequency actual measurement.

3. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1; it is characterized in that; the current quick adaptive setting model of described band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model comprises: vacuum circuit-breaker current quick adaptive setting model and FC loop current fast tripping protection adaptive setting model, and FC loop current fast tripping protection adaptive setting model comprises again: adaptive setting model and the adaptive setting model having big current locking tripping operation outlet function without big current locking tripping operation outlet function:

A, vacuum circuit-breaker current quick adaptive setting model

(1) operating current: adjust by the magnetizing inrush current escaping phase shifting transformer, namely

I _oph＝KI _e

In formula: K is multiple, depending on transformer capacity, the concrete span of K is as follows:

6300kVA and following: 7 ~ 12;

6300kVA～31500kVA：4.5～7.0；

40000kVA～120000kVA：3.0～6.0；

120000kVA and more than: 2.0 ~ 5.0;

(2) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{k.\min }^{\left(2\right)}}{I_{\mathrm{oph}}{n}_{\mathrm{TA}}}\≥2$

In formula: n _tAfor (high-voltage switch gear inlet wire) CT no-load voltage ratio that protection uses;

for in protection zone, high-pressure side, line to line fault flows through on high-tension side electric current;

I _ophfor current quick operating current;

(3) action delay: for the mode all adopting vacuum circuit-breaker, get 0.05s;

B, FC loop current fast tripping protection adaptive setting model:

A, without big current locking tripping operation outlet function adaptive setting model, as follows:

(1) operating current: identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, that is: I _oph=KI _e;

(2) action delay: t _opget the maximum duration of fuse fuse failure, span is: 0.3 ~ 1s;

B, big current locking is had to trip the adaptive setting model of outlet function, as follows:

(1) operating current: identical with vacuum circuit-breaker current quick-breaking operating current adaptive setting model, that is: I _oph=KI _e;

(2) latching current definite value I _art

${20I}_{\mathrm{TA}.n}\≥I_{\mathrm{art}}=\frac{I_{\mathrm{brk}}}{K_{\mathrm{rel}}{n}_{\mathrm{TA}}}$

In formula: I _artfor big current locking definite value;

I _brkfor vacuum contactor allows turn-off current;

K _relfor safety factor, get 1.3 ~ 1.5;

(3) action delay

t _op＝0.05～1s；

(4) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{\mathrm{art}}}{I_{\mathrm{oph}}}\≥2.$

4. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1; it is characterized in that; the described current quick adaptive setting model not with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model also comprises: vacuum circuit-breaker current quick adaptive setting model and FC loop current fast tripping protection adaptive setting model, and FC loop current fast tripping protection adaptive setting model comprises again: adaptive setting model and the adaptive setting model having big current locking tripping operation outlet function without big current locking tripping operation outlet function:

C, vacuum circuit-breaker current quick adaptive setting model, as follows:

(1) operating current: adjust by the principle escaping the maximum starting current of motor, namely

I _oph＝K _relK _st·I _e

In formula: K _relfor safety factor gets 1.5;

K _stfor motor starting current multiple, calculate by measured value, span is 6 ~ 8;

(2) sensitivity check

$K_{\mathrm{sen}}=\frac{I_{k.\min }^{\left(2\right)}}{I_{\mathrm{oph}}{n}_{\mathrm{TA}}}\≥2$

In formula: n _tAfor CT no-load voltage ratio;

for motor entrance minimum line to line fault electric current one sub-value;

I _ophfor current quick operating current;

(3) action delay: for the mode all adopting vacuum circuit-breaker, operate time gets 0.05s;

D, FC loop current fast tripping protection adaptive setting model, as follows:

(1) without the adaptive setting of big current locking tripping operation outlet function:

(a) operating current:

Identical with vacuum circuit-breaker current quick-breaking operating current synchronizing calculation method, i.e. I _oph=K _relk _sti _e;

(b) action delay: t _opget the maximum duration of fuse fuse failure, span is: 0.3 ~ 1s;

(2) the adaptive setting model of big current locking tripping operation outlet function is had, as follows:

(a) operating current:

Identical with vacuum circuit-breaker current quick-breaking operating current synchronizing calculation method, i.e. I _oph=K _relk _sti _e;

(b) latching current setting value I _artcalculate

${20I}_{\mathrm{TA}.n}\≥I_{\mathrm{art}}=\frac{I_{\mathrm{brk}}}{K_{\mathrm{rel}}{n}_{\mathrm{TA}}}$

In formula: I _artfor big current locking definite value; I _brkfor vacuum contactor allows turn-off current; K _relfor safety factor, get 1.3 ~ 1.5;

(3) action delay:

t _op＝0.05～1s；

(4) sensitivity check:

$K_{\mathrm{sen}}=\frac{I_{\mathrm{art}}}{I_{\mathrm{oph}}}\≥2.$

5. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1, is characterized in that, described overcurrent protection adaptive setting model is:

(a) operating current

For band phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, operating current I _opadjust by escaping phase shifting transformer secondary rated current; For not being with phase shifting transformer high-pressure frequency-conversion motor protection adaptive setting model, operating current I _opadjust by escaping motor secondary rated current;

$I_{\mathrm{op}}=\frac{K_{\mathrm{rel}}}{K_r}{I}_e$

In formula: K _relfor safety factor, get 1.05 ~ 1.2;

K _rfor resetting ratio, get 0.85 ~ 0.95;

(b) action delay

t _op＝(1-1.1)t _qd

In formula: t _opfor overcurrent protection action delay;

T _qdfor the motor start-up time.

6. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1, is characterized in that, described unbalanced fault protection adaptive setting model comprises: negative phase-sequence I segment protect adaptive setting model and negative phase-sequence II segment protect protection seting computation model:

(a) negative phase-sequence I segment protect adaptive setting model:

By when escaping unsymmetrical short-circuit outside district when motor negative phase-sequence feedback current and motor start-up due to the negative-sequence current that current transformer error and transient characterisitics occur, and ensure that motor has enough sensitivity synthesis to consider to calculate when larger load two-phase operation and motor interior unsymmetrical short-circuit:

Operating current I _2.1dz:

I _2.1dz＝(0.6～1.4)I _e

Action delay t _2.1dz:

1) if device provides negative phase-sequence reverse blocking function, t _2.1dz=(0.5 ~ 1) s;

2) if device does not provide negative phase-sequence reverse blocking function, t _2.1dz=(5 ~ 6) s, the misoperation that the negative-sequence current produced to escape the outside two-phase short-circuit fault of motor causes;

(b) negative phase-sequence II segment protect adaptive setting model:

By escaping maximum negative-sequence current possible when motor normally runs and motor compared with there being enough sensitivity to consider during Smaller load two-phase operation, using as sensitive unbalance protection, can alarm be selected:

Operating current I _2.2dz:

I _2.2dz＝(0.2～0.35)I _e

Action delay t _2.2dz: get the start-up time being greater than motor.

7. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1, it is characterized in that, described Over Heat Protection Setting Calculation model comprises: motor occur overheated time Over Heat Protection Setting Calculation model and based on IEC60255-8 overheated with real index curve rise Over Heat Protection Setting Calculation model;

When () motor occurs overheated a, temperature raises with the initial climbing speed of the exponential curve of reality always, and its model is

${\∫}_0^t[{\left(\frac{I_{\mathrm{eq}}}{I_e}\right)}^2-{1.05}^2]\mathrm{dt}\≥\mathrm{\τ}$

$I_{\mathrm{eq}}^2=K_1{I}_1^2+K_2{I}_2^2$

In formula: I _efor motor secondary rated current;

I _eqfor causing the equivalent current of heating;

τ is electric motor overheating time constant;

I ₁, I ₂for the positive and negative sequence electric current of motor;

K ₁, K ₂for positive and negative sequence heating effect of current coefficient, K in starting process of motor ₁get 0.5 ~ 1, K ₂get 3 ~ 10;

B () is as follows based on the overheated Over Heat Protection Setting Calculation model with the rising of real index curve of IEC60255-8:

${\∫}_0^t\frac{1}{\ln \left(\frac{I_{\mathrm{eq}}^2-{\mathrm{\ξI}}_{\left[0\right]}^2}{I_{\mathrm{eq}}^2-I_{\∞}^2}\right)}\mathrm{dt}\≥\mathrm{\τ}$

In formula: I _[0]for overheated front motor current;

ξ is a coefficient of considering under motor normal operation to dispel the heat, and gets 50%;

I _∞for overtemperature protection starting current, span is (1.05 ~ 1.15) I _e.

8. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1; it is characterized in that, described ground protection adaptive setting model comprises: isolated neutral system one-phase ground protection adaptive setting model and Neutral Point Through Low Resistance system one-phase ground protection adaptive setting model:

A, isolated neutral system one-phase ground protection adaptive setting model are as follows:

(1) operating current

Calculate by the earth current flowing through protection installation place when escaping single-phase earthing outside district, that is:

$I_{\mathrm{op}.0}=K_{\mathrm{rel}}{I}_k^{\left(1\right)}$

In formula: I _op.0for single-phase earthing zero sequence excess current protection act electric current;

K _relfor safety factor, get 2.5 ~ 3s when protection act also trips, protection act gets 2 ~ 2.5s when signal;

for the earth current of protected equipment supply short dot during single-phase earthing outside dorsal zone, i _efor protected equipment positive direction capacitance current sum during single-phase earthing outside dorsal zone;

(2) operate time

When 3 ~ 10kV earth current is not less than 10A, get 0.5 ~ 1s;

When 3 ~ 10kV earth current is less than 10A, to 300MW and above unit, if when meeting selectivity and sensitivity requirement, get 0.5 ~ 1s;

When 3 ~ 10kV earth current is less than 10A, during as sensitivity can not be met and optionally require, can action in signal, get 0.5s;

(3) sensitivity test

$K_{\mathrm{sen}}^{\left(1\right)}=\frac{I_{\mathrm{k\Σ}}^{\left(1\right)}-I_k^{\left(1\right)}}{I_{\mathrm{op}.0}}\≥1.5$

In formula: during for protected equipment generation single-phase earthing, earthing capacitance current two sub-value that fault point is total;

B, Neutral Point Through Low Resistance system one-phase ground protection adaptive setting model are as follows:

(1) operating current: get the greater in both following (a) and (b);

A () calculates by escaping single-phase earthing outside district

$I_{\mathrm{op}.0}=K_{\mathrm{rel}}{I}_k^{\left(1\right)}$

In formula: K _relfor safety factor, get 1.1 ~ 1.15;

B () calculates by escaping busy hour unsymmetrical current

I _op.0＝K _relI _umb

In formula: K _relfor safety factor, get 1.3;

I _umbfor busy hour unsymmetrical current;

I _umb≤ (0.1 ~ 0.15) × I _n, I _nfor feeder line rated current;

(2) action delay: 0 ~ 0.05s;

(3) sensitivity check

$K_{\mathrm{sen}}^{\left(1\right)}=\frac{I_{\mathrm{k\Σ}}^{\left(1\right)}}{I_{\mathrm{op}.0}}\≥2$

In formula: for single-phase earthing of small current earthing system electric current.

9. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1, is characterized in that, described under-voltage protection adaptive setting model comprises as follows:

(1) for the motor with intermediate system, the operation voltage of low-voltage variation:

U _dz＝(0.6～0.7)U _N

Action delay: 0.5 ~ 1.5s;

(2) for there is the motor automatically dropping into stand-by machine, the operation voltage of under-voltage protection:

U _dz＝(0.4～0.5)U _N

Action delay: 5 ~ 10s.

10. high-pressure frequency-conversion motor protection adaptive setting model according to claim 1, is characterized in that, described rotation-clogging protection adaptive setting model is as follows:

(1) below 600MW unit:

Operating current: I _dz=(1.3 ~ 1.5) I _e;

Action delay: t _op.set=15 ~ 20s;

(2) the fan-type unit of more than 600MW:

Calculate by escaping sort time overcurrent

Operating current: I _dz=(1.8 ~ 2.0) I _e;

Action delay: t _op.set=15 ~ 20s;

Or

Adjust as operating current setting value: I _dz=1.5I _e;

Action delay: t _op.set=25 ~ 30s;

(3) 600MW is with charging pump class unit:

Operating current: I _dz=(1.3 ~ 1.5) I _e;

Action delay: t _op.set=15 ~ 20s.