RU2316098C1 - Method for detecting asynchronous mode in power system - Google Patents

Abstract

FIELD: electrical engineering; automatic emergency management facilities for power-systems.

SUBSTANCE: proposed method includes calculation of impedance vector as voltage-to-current vector ratio in point under check. Impedance vector projection onto axis turned in complex plane of impedances relative to imaginary axis through angle supplementing rated angle of equivalent power transmission impedance to 90 deg. is calculated. Resistance up to electrical center of oscillations is found by projection. Disposition of center of oscillations on line section under check is recorded when projection value occurs within specified range. Vector of voltage being measured onto axis turned in complex plane relative to power transmission current vector through same additional angle is calculated. Power transmission angle is calculated by voltage projection using simple trigonometric function. Asynchronous mode onset is detected by coincidence between signs of power transmission angle and those of its first and second time derivatives. Asynchronous mode hazard is recognized by excess of first derivative above admissible value calculated with aid of "angle-slip" boundary phase functions and parameters of original modes.

EFFECT: enhanced selectivity and stability of asynchronous mode detection and reduced number of automatic management inadequate responses.

2 cl, 7 dwg

Description

The invention relates to the field of electrical engineering, in particular to emergency automation of power systems (ES), the structure of which includes automatic elimination of asynchronous mode (ALAR), which identifies and terminates this mode by dividing the system (DS) or resynchronization (PCX).

электропередачи, напряжение

в контролируемом узле ЭС, сопротивление

и мощность

В этом способе по

с помощью реле сопротивления устанавливается факт попадания электрического центра качаний (ЭЦК) на контролируемый участок сети (сечение АР), а по

посредством реле мощности - переход δ через критическое по условиям устойчивости значение δ_кр=(120°÷180°) [1, стр.40-45]. Переориентация реле мощности в области срабатывания реле сопротивления служит признаком возникшего АР.The method of detecting asynchronous mode (AR) in ES on the first cycle according to local operating parameters in the system node, which is represented as a power transmission relative to the controlled section at a two-frequency AR, is widely known [1, p. 16-36]. These parameters, functionally related to the angle of electric transmission δ (the angle between equivalent EMF at its ends), are usually represented by vector current

power transmission voltage

in the controlled ES unit, resistance

and power

In this method, by

using the resistance relay, the fact of the hit of the electric swing center (ECC) on the controlled section of the network (section of the AR) is established, and

by means of a power relay - transition δ through a critical value under stability conditions δ _cr = (120 ° ÷ 180 °) [1, p. 40-45]. Reorientation of the power relay in the field of operation of the resistance relay is a sign of the arising AR.

The disadvantages of this method result from the ambiguity of the dependence of the parameters used on the angle δ, which does not allow acceptable accuracy to determine its values in the required range (90 ° <δ <270 °) and the slip value s = dδ / dt in the whole package of calculation schemes and modes. For this reason, the selectivity and stability of the functioning of the method and the ALAR devices implementing it are reduced with the hard-wired characteristics of the resistance and power relays. To achieve an acceptable level of stability of functioning, it is necessary to fix the fact of the occurrence of AR in the second half of the cycle with values of the angle δ significantly exceeding δ _cr (δ> 180 °), and the detection of a threat of developing AR (δ <δ _cr ) is possible if we neglect the selectivity with respect to to deep synchronous swings (SK).

There is also a known method for detecting AR, based on modeling stresses at two power points that limit the controlled area, and the real angle δ is calculated from the travel time curves of these vectors and the voltage vector at the measurement point [2].

от окружности и колебаниям вычисляемого угла δ_m относительно δ. Это особенно влияет на селективность выявления угрозы и момента возникновения АР, когда используются производные δ_m по времени. Увеличение числа замеров

для сглаживания колебаний методами аппроксимации вызовет снижение селективности за счет замедления фиксации АР до и в момент нарушения устойчивости.When calculating δ in the rate of AR based on stress hodographs, acceptable results can be obtained only under ideal or close conditions. However, the out-of-phase and self-pumping of generators inside asynchronously running groups, the distribution of power take-offs that impede modeling, changing the circuit parameters and load during the development of the accident, lead to strong deviations of the hodographs

from the circle and the oscillations of the calculated angle δ _m with respect to δ. This especially affects the selectivity of threat detection and the moment of occurrence of AR when time derivatives of δ _m are used. Increase in number of measurements

to smooth the oscillations by approximation methods, it will cause a decrease in selectivity by slowing down the fixation of AR before and at the moment of stability violation.

The closest in technical essence and the achieved results to the proposed method is a method according to which currents and voltages in a power transmission unit are measured by scalar and vector parameters, the transmission angle δ _l is determined on the basis of these measurements, replacing it with the transmission angle δ (indicated in [3] δ ₁₂ ), calculate the first and second derivatives of δ _l in time, determine the reactance X _min from the measurement point to the point with minimum voltage (TMN) and the sign of the time derivative of the active power P _n , transmitting transmitted by power transmission, and the moment of occurrence of AR is recorded by the coincidence of the signs of δ _l and its derivatives, if the sign of the derivative P _{n is} opposite to them, and the TMN is located within the protected section of the network (X _min is in the specified range) [3]. In this case, it is assumed that 90 ° <δ <180 °, when the TMP and the ECC practically coincide.

The assumption that δ and δ _{l are} approximately equal is quite acceptable if the modeled points are sufficiently close to the points of application of equivalent EMF, which is possible only under conditions favorable for modeling (long transits without significant power take-offs, simple, close to radial structure network). However, in practice, these conditions are rarely fulfilled, which forces to narrow the controlled area, in addition to rebuild from external ARs. In such cases, the angle δ _L can significantly (by 60 ° ÷ 70 °) deviate from δ, especially at δ = (80 ° ÷ 120 °) (see figure 1, curves 1 and 2).

The disadvantages of this method are the low selectivity and stability of functioning.

The incompleteness of the first property is caused by the identification of the calculated angle δ _l with the real angle δ. Moreover, in a number of modes, the signs of the second time derivatives of δ _l and δ may not coincide. Imagine their relationship in a convenient form for analysis:

Even for the simplest homogeneous power transmission without power takeoff, the following statements are true:

1. The sign of the term C in AR on a given section of the network is determined only by the sign ds / dt, because factor A is always positive (see figure 2, curve 1), and reaches its maximum value at δ = ± 180 °.

2. The sign of the term B is determined by the sign dA / dδ (s ² > 0), which in the range - 180 ° <δ <180 ° coincides with the sign of δ and is opposite to it for other values of δ in the range - 360 ° <δ <360 ° ( see Fig. 2, curve 2), and extreme values of dA / dδ occur at δ = ± (120 ° ÷ 150 °), and zero at δ = ± 180 °, which is confirmed by the nature of the change in the derivative with respect to δ of the function shown curve 1 in figure 2.

Therefore, due to the term B, if | B |> | C |, it is possible to fix the moment of occurrence of AR in deep SCs, especially taking into account the action of automatic stability prevention (APS) and real circuit-mode conditions with a more complex dependence of δ _l on δ .

On the other hand, during the development of AR, it is not the moment that is recorded, but the threat of its occurrence due to the same term B, which can cause a change in the sign of d ² δ _l / dt ² much earlier than the sign of d ² δ / dt ² changes. At the same time, the selectivity to detect the threat of AR is not always ensured.

к вектору

эквивалентного сопротивления электропередачи в плоскости R, jX.In addition, due to a violation of the stability of the operation, it is possible to fix a close external AR if the angle φ _{e of the} equivalent transmission resistance is significantly greater than the angle φ _{l of the} resistance of the controlled section of the network, because for δ> δ _cr , all necessary conditions are satisfied, incl. and X _min <X _l due to the greater slope of the hodograph

to the vector

equivalent power transmission resistance in the plane R, jX.

The task to which the stated proposal is directed is to increase the selectivity and stability of functioning.

The technical result obtained is manifested in a decrease in the number of failures, unnecessary and false alarms, where this invention can be used, which together reduces the damage from possible accidents in modern complex power systems.

как отношение вектора напряжения к вектору тока в контролируемом узле, вычисляют проекцию Z_0m вектора

на ось jX_m, повернутую в комплексной плоскости сопротивлений относительно мнимой оси jX на угол α, дополняющий расчетный угол φ_э эквивалентного сопротивления электропередачи до 90°, фиксируют попадания значений U_m и Z_0m в установленные для них диапазоны как дополнительное условие выявления асинхронного режима по контролируемому сечению, определяют знак U_m в момент t₁ входа его значений в установленный диапазон как знак угла δ, вычисляют в этом диапазоне угол электропередачи при его положительном знаке по формулеThe problem is solved in that in the known method, according to which the currents and voltages in the power transmission unit are measured by scalar and vector parameters, the transmission angle δ is determined on the basis of these measurements, its first and second time derivatives are calculated, and the moment of occurrence of the asynchronous mode is recorded by coincidence marks angle δ and derivatives thereof, further comprises calculating a projection vector of the measurement voltage (U _m) on the axis, rotated in the complex plane with respect to the transmission of the current vector by the angle α, opolnyayuschy calculated angle φ _e equivalent resistance power to 90 °, calculated impedance vector

as the ratio of the voltage vector to the current vector in the controlled node, calculate the projection Z _{0m of the} vector

on the axis jX _m , rotated in the complex plane of the resistance relative to the imaginary axis jX by an angle α, supplementing the calculated angle φ _{e of the} equivalent transmission resistance up to 90 °, the occurrence of the values of U _m and Z _0m in the ranges set for them is recorded as an additional condition for identifying the asynchronous mode controlled cross-section, determine the sign of U _m at the time t _{1 the} entrance of its values to the specified range as a sign of the angle δ, calculate the transmission angle in this range with its positive sign by the formula

δ ⁽⁺⁾ = 2 arccos (U _m / U _n );

δ ^(-) = (2 · π-δ ⁽⁺⁾ ),

where U _n is the nominal voltage in the power node, and fix the asynchronous mode with acceleration with a positive sign U _m and the asynchronous mode with braking with a negative sign U _m .

Furthermore, in addition to each step of the measurement is calculated from the given boundary phase trajectories "angle - slip" with regard to the parameters of the starting mode allowed by the conditions of stability value s _dop first derivative of the angle δ with respect to time (s) and fix the threat of an asynchronous mode if s greater s _add .

A comparative analysis of the features of the claimed solution and the features of analogues and prototype indicate its compliance with the criterion of "novelty."

The features of the characterizing part of the claims solve the following functional tasks:

1. The sign "... calculate the projection of the vector of the measured voltage on the axis, rotated in the complex plane relative to the vector of the power transmission current by an angle that complements the calculated angle of the equivalent power transmission resistance to 90 ° ..." allows, firstly, to determine the angle δ as elementary function of U _m and, secondly, setting the limits of change of U _m , limit the obtained values of δ to a range including δ _cr , and thereby ensure a high degree of correspondence between the calculated and real values of the angle δ.

2. The sign "... calculate the projection of the vector of the impedance on the axis, rotated in the complex plane of the resistance relative to the imaginary axis by an angle that complements the calculated angle of the equivalent power transmission resistance to 90 ° ..." allows you to more accurately and directionally measure the distance to the ECC, which increases the stability of functioning with external and internal ARs close to the boundaries of the controlled network section.

3. The sign "... calculated according to the specified boundary phase trajectories" angle - slip ", taking into account the parameters of the initial mode, the value of the first derivative of the angle of transmission over time, permissible under the stability conditions ..." makes it possible to selectively identify the threat of AR, increasing the selectivity of the whole method .

и

по концам передачи, и сопротивлениями

и

, на которые делится ее эквивалентное сопротивление

контролируемым узлом 0; на фиг.4 изображена векторная диаграмма электропередачи - эквивалента ЭС при двухчастотном АР, - представленной на фиг.3; на фиг.5 показаны годографы сопротивления Z в контролируемом узле в режимах внутренних АР с размещением ТМН слева при s>0 (годограф 1) и справа при s<0 (годограф 2) от точки измерения 0, а также показаны параметры Z_0m и U_m в их взаимосвязи и заданных пределах изменения; на фиг.6 изображен годограф

при близком внешнем АР и показаны параметры, контролирующие зону размещения ЭЦК по известному и предлагаемому способам; на фиг.7 представлена функциональная схема реализации заявляемого способа.Figure 1 shows the change in the angle of the simulated transmission angle δ _l when the ECC is in the controlled area (curve 1) and beyond (external AR) - curve 2; figure 2 shows the change in the first and second derivatives of δ _l by δ - curve 1 and curve 2, respectively; figure 3 presents the equivalent circuit of the power transmission - the equivalent of ES in dual-frequency AR with EMF

and

at the ends of the transmission, and resistances

and

into which its equivalent resistance is divided

controlled node 0; figure 4 shows a vector diagram of power transmission - the equivalent of ES with two-frequency AR, - presented in figure 3; figure 5 shows the hodographs of resistance Z in the monitored node in the modes of internal AR with the location of the HMI on the left for s> 0 (hodograph 1) and on the right for s <0 (hodograph 2) from the measurement point 0, and also shows the parameters Z _0m and U _m in their relationship and the specified limits of change; figure 6 shows the hodograph

with a close external AR, parameters are shown that control the zone of ECC placement according to the known and proposed methods; figure 7 presents a functional diagram of the implementation of the proposed method.

и

соответственно, причем последний отстает от вектора

на угол φ_э, а от

на угол φ. Следовательно, проекция U_m вектора

на ось, повернутую относительно

на угол α, может быть найдена какThe voltage in the controlled node 0 and the current transmission (Fig.2) are shown in the vector diagram (Fig.3) by vectors

and

accordingly, the latter lagging behind the vector

angle φ _e , and from

angle φ. Therefore, the projection U _{m of the} vector

on an axis rotated relative to

at an angle α, can be found as

и

α - угол, дополняющий расчетный φ_э, эквивалентного сопротивления электропередачи до 90°; Z=U/I - модуль полного сопротивления в точке измерения 0.where φ is the angle between the vectors

and

α is the angle complementary to the calculated φ _{e of the} equivalent transmission resistance of up to 90 °; Z = U / I - the impedance module at the measurement point 0.

в ТМН совпадают по модулю, т.е. |U_m|=U_тмн Отличие U_m от U_тмн состоит в том, что U_m меняет свой знак при переходе δ через значения ±180°, а U_тмн всегда положительно.Obviously, U _m and voltage

in TMN coincide modulo, i.e. | U _m | = U _mpn The difference between U _m and U _mpn is that U _m changes its sign when δ passes through the values of ± 180 °, and U _{mpn is} always positive.

Therefore, from a given range of U _m, one can not only determine the range of the angle δ close to 180 ° (working range), but also find the sign of this angle and its derivative s as the sign of the projection U _m at the moment of its entry into the mentioned range (signs δ, s and U _{m are the} same until the last change in the AP cycle). In addition, the most important property of U _m is its connection through a simple function with angle δ.

Assume that

и U_ц.п - вектор напряжения в ЭЦК и его проекция на биссектрису угла δ.Where

and U _c.p is the stress vector in the ECC and its projection onto the bisector of the angle δ.

This assumption is quite valid at 90 ° <δ <270 °, because the error in this range does not exceed 1% for real values of k = E ₁ / E ₂ (0.8 <k <1.25 [1, p. 19-20]).

можно с учетом (3) получить следующие выражения:Knowing the relative remoteness of α _c the power transmission (Fig.3) ETSK from the point of application

taking into account (3), we can obtain the following expressions:

where U _n is the rated voltage in the controlled node.

на U_н вносит погрешность по нашим оценкам не более 5%, т.к. E₁ и Е₂ изменяются в диапазоне от 0.9·U_н до 1.1·U_н при реальных значениях s [1, стр.17].Replacement

according to our estimates, the error on U _n is no more than 5%, because E ₁ and E ₂ vary in the range from 0.9 · U _n to 1.1 · U _n at real values of s [1, p.17].

The joint solution of (2) and (5) allows us to establish a relationship between δ and Um through an elementary trigonometric function:

where δ _m is the angle modeling δ.

The absolute error Δδ = δ-δ _{m of the} simulation, as shown by the calculations, is not ± 6%, for the accepted extreme values of the working range (δ = 90 ° and δ = 270 °), decreases to zero at δ = 180 ° (U _m = 0 ) The deviation of φ _e from the actual values in the package of design schemes of ES also introduces an error proportional to this deviation (almost ± 10 °). However, the total error Δδ does not exceed ± 15 °, which is significantly less than when δ is replaced by δ _l [3], when Δδ can reach (60 ° ÷ 70 °) (see above on page 2). The use of δ _m instead of δ does not affect the accuracy of determining the sign of δ and its derivatives, which significantly increases the selectivity of the proposed method.

As noted, the established range of variation of U _m corresponds to the working range of the angle δ, in which its values are calculated depending on the sign of δ, defined on the border of this range as the sign of U _m :

where δ ⁽⁺⁾ and δ ^(-) is the angle modeling δ at its positive and negative values, respectively.

на ось jX_m, повернутую в комплексной плоскости на угол α=90°-φ_э. Эта проекция, как показано на фиг.4, может быть определена по формулеIn the proposed method, in addition to U _m and the angle δ functionally associated with it, the projection Z _{0m of the} vector is calculated

on the axis jX _m , rotated in the complex plane by an angle α = 90 ° -φ _e . This projection, as shown in figure 4, can be determined by the formula

, R и X - активная и реактивная составляющие

.where Z is the module

, R and X are the active and reactive components

.

на ось R_m, образующую с осью jX_m декартову систему координат, вычисляемая по формулеIn fact, Z _0m corresponds to the resistance from the measurement point (node 0 at the power transmission) to the HMI, and hence the ESC in the working range of angles δ, and the sign of the projection Z _{0m is} positive when the ESC is placed to the right of the node 0 and is negative otherwise (φ _e- φ) <90 °. These modes are displayed by the hodographs 1 (s> 0) and 2 (s> 0) in Fig.6. Also shown is the projection Z _{m of the} vector

on the axis R _m , forming with the axis jX _{m the} Cartesian coordinate system calculated by the formula

or subject to (2)

From (9) - (11), the connection between the projections U _m , Z _0m and Z _m is obvious. The values of Z _m for s> 0 and 0 ° <δ <180 ° are positive (φ _e -φ> 0), and for s <0 and - 180 ° <δ <0 ° - negative (φ _e -φ <0).

In Fig. 5, the signs of the projections shown are indicated by the indices "+" and "-". In addition, the limit values for the ranges set for these values are shown:

Here, taking into account (11) Z _cf = U _cf / I, where U _cf defines the boundaries of the range specified for U _m :

в область срабатывания как знак U_m.According to the proposed method, AR will be detected at δ> δ _cr , when conditions (12) - (14) are satisfied and the signs of the angle δ and its first and second derivatives with respect to time coincide, and δ is calculated according to (7) or (8) depending from its sign determined at time t _{1 of the} entry of the hodograph

into the response area as a sign of U _m .

Since the latter corresponds to the slip sign s = dδ / dt, ARs with acceleration are fixed at U _m > 0, and ARs with braking are fixed at U _m <0.

In the known method also determine the resistance to TMP, but its reactive component X _min , indicated in [3] X _tn .

a также определяя реактивную составляющую Х_0m вектора

получим формулы, по которым можно сравнить методы оценки расстояния до ТМН по известному и предлагаемому способам:Transforming the expression for X _TMN taking into account the fact that Q ₁ = U ₁ · I ₁ · sinφ, P ₁ = U ₁ · I ₁ · cosφ, Z = U ₁ / I ₁ ,

a also determining the reactive component X _{0m of the} vector

we get the formulas by which you can compare the methods for estimating the distance to the TMP according to the known and proposed methods:

Obviously, the difference between the calculation results according to (15) and (16) is connected to a greater extent by the inequality φ _l and φ _e , since in the case when φ _l = φ _e , this difference with δ _cr <δ <180 ° (R is small) usually does not exceed 10% in the direction of increasing or decreasing X _min , depending on the combination of the signs R and X. Therefore, for a visual comparison of the methods of Fig. 6, the resistance X _min at a close external AR was determined according to (16) with the replacement of φ _e by φ _l . Here φ _e > φ _l , s <0, Z ₀₁ = Z _l , Z ₀₂ = 0.

Obviously, in a certain range for δ> δ _cr in the prototype [3] all the conditions of AR fixation are satisfied, since X _min <X _l , while in the proposed method, condition (13) is not satisfied (Z _0m > Z ₀₁ ) and the external AR is not detected, which indicates a higher stability of operation when deviations φ _e from φ _l in the design package of schemes ES. An additional limitation of the working range δ (according to f. (5), on p. 174 in [4]) leads to a slowdown in the detection of ARs in the controlled area, especially if the DTM is shifted to its end. At the same time, it is not the moment that is recorded, but the fact of the occurrence of AR (δ> δ _cr ), which can lead to the simultaneous operation of ALAR devices of parallel lines and a violation of the stability of the automation as a whole.

In addition to fixing the moment of occurrence of AR, the proposed method allows to identify the threat of its development at δ> δ _cr . For this, in addition, in the response zone, when conditions (12) - (14) are fulfilled, at each measurement step, the angle – slip angle and slip parameters are calculated using the given boundary phase trajectories, taking into account the parameters and the initial mode, the value of s _additional slip s, admissible under stability conditions, is fixed the threat of AR with acceleration (U _m > 0) or braking (U _m <0) when

Boundary trajectories are defined, for example, by an approximating function, as in [5, f. (173) on p. 144], from which

where δ ₀ is the value of δ in the initial mode; δ _cf - a certain value of δ that determines the approximation parameters (δ _cp ≈180 °); k ₁ and k ₂ are constant coefficients providing the greatest correspondence of phase trajectories and function (18). It should be noted that in (17) and (18) the absolute values of s and δ are used. We also note that with a positive error, δ, s decreases, and with a negative error it increases. The same thing happens with s _add by (18). Therefore, the execution time (17) depends little on the simulation error δ by the proposed method, which indicates its high selectivity.

Figure 7 presents a simplified (without blocking from short-circuit) implementation scheme of the proposed method.

The circuit contains a block 1 of current and voltage sensors, a block 2 of the functional signal processing, a shaper 3 of recognition parameters AR, a limiter 4 of the range of variation of voltage U _m , a limiter of 5 of the range of change of resistance Z _0m , a clamp 6 of the sign of voltage U _m , shaper 7 of the angle of transmission δ, shaper 8 of derivatives of angle δ, block 9 of fixing the moment of occurrence of AR, block 10 of fixing the threat of occurrence of AR, and conjunctors 11-16 (logical elements "AND"). All input and output signals of the blocks are also indicated here (Y _i are logical signals).

The scheme works as follows. The input signals from the measuring transformers of the controlled ES unit are fed to the input of the circuit through block 1, which is two parallel channels of intermediate converters (sensors) of voltage and current. The output signals of these sensors (block 1) are linearly connected to the input, having the form (usually voltage) and ranges of variation suitable for use, for example, in the digital part of the circuit (ADC).

с помощью цифровой техники.Block 2 carries out frequency filtering and decomposition of the input signals into orthogonal components with the subsequent calculation of the parameters necessary further

using digital technology.

In block 3, the parameters U _m and Z _0m are calculated according to (2) and (9), respectively. Using blocks 4 and 5, the ranges of variation of U _m and Z _0m possible for a given section are specified. The output signals Y ₁ and Y _{2 of} these blocks take a logical “1” value only if conditions (14) and (12) are met, respectively. When condition (14) arises, the sign U _m is fixed by block 6 (Y ₃ = 1 for a positive sign and Y ₃ = 0 for a negative). Depending on the sign of U _m according to (7) or (8) in block 7, the angle of transmission δ is calculated in the operating range (Y ₁ = 1). Its first s and second ds / dt time derivatives are obtained at the upper and lower outputs of block 8, respectively. The signs δ, s, and ds / dt are converted in block 9 into logical signals, similarly to what is done in block 6. The coincidence of the values of these signals (Y ₄ = 1) occurs at the moment of occurrence of the AR. Condition (17) is checked in block 10, and its fulfillment (Y ₅ = 1) indicates a threat of AR. Here, s _{additional is} estimated from the given boundary phase trajectories, for example, using (18), and the function of "storing" the value δ _{0 of the} angle δ in the preceding accident ES mode is implemented.

The output logic signals Y ₆ = Y ₂ · Y ₄ and Y ₇ = Y ₂ · Y _{5 of the} conjunctors 11 and 12, respectively, can take the value “1” only when placing the TMN (ECC) on the controlled section of the network (Y ₂ = 1) and fixing moment (Y ₄ = 1) or threat (Y ₅ = 1) of the occurrence of AR.

.Conjunctors 13-16 separate each of the signals Y ₆ and Y ₇ depending on the sign of U _m (values of Y ₃ ), which coincides with the signs of slip

.

Sources of information used in the preparation of the description of the invention

1. Gonik Y.E., Iglitsky E.S. Automatic elimination of asynchronous mode. - M .: Energoatomizdat, 1988;

2. Patent RU 2204877 C1, MCP H02J 3/24. 2003 year

3. Patent RU 2199807 C2, manual gearbox H02J 3/24. 2003 year

4. Zelakov S.I., Lisitsin A.A., Katz P.Ya., Edlin M.A. Adaptive digital automation of elimination of asynchronous modes // OJSC "Institute" Energosetproekt ", Sat. reports of the scientific-practical conference "Actual problems of relay protection, emergency control, stability and modeling of power systems in the context of restructuring of the electric power industry." - M.: Publishing House NTs ENAS 2001, p.172-179.

5. Rosenblum F.M. Measuring bodies of emergency automation of power systems. - M .: Energoatomizdat, 1981: - 160 p., Ill.

Claims (2)

1. A method for detecting the asynchronous mode in the power system, according to which currents and voltages in the power transmission unit are measured by scalar and vector parameters, the transmission angle is determined on the basis of these measurements, its first and second time derivatives are calculated, and the moment of the appearance of the asynchronous mode is determined by coincidence of the signs of the angle power transmission and its derivatives, characterized in that it further computes the projection of the vector of the measured voltage on the axis, rotated in a complex plane relative to the vector then and power transmission by an angle that complements the calculated angle of equivalent power transmission resistance to 90 °, calculates the impedance vector as the ratio of the voltage vector to the current vector in the monitored node, calculates the projection of the impedance vector on an axis rotated in the complex plane of the resistance relative to the imaginary axis by an angle that complements the calculated angle of the equivalent power transmission resistance is up to 90 °; the hit values of the projections of the vectors of the measured voltage and impedance are fixed in the mouth tained for each of these ranges as an additional condition detecting asynchronous operation of the controlled section, determine the sign of the projection of the measured voltage at the time of input of its values within the specified range as a token transmission angle calculated in this range transmission angle at its positive δ ⁽⁺⁾ and negative δ ^(-) signs by the formula δ ⁽⁺⁾ = 2 arccos (U _m / U _n ), δ ^(-) = (2 · π-δ ⁽⁺⁾ ), where U _n is the nominal voltage at the power transmission node, a U _m is the projection of the measured voltage vector, and the asynchronous mode with acceleration at a positive sign of the projection of the measured voltage vector and the asynchronous mode with braking at its negative sign are fixed. 2. The method according to claim 1, characterized in that in addition, at each measurement step, the “angle-slip” is calculated according to the specified boundary phase trajectories, taking into account the parameters of the initial mode, the value of the first derivative of the angle of transmission over time is stable under the conditions of stability and the threat of an asynchronous mode is fixed if the first derivative of the transmission angle is greater than the permissible value.

Images