JP5450005B2 - System stabilization device - Google Patents

Description

  The present invention relates to a system stabilizing device that stabilizes the remaining generators by disconnecting a part of generators from a power system at a high speed in a phenomenon in which a plurality of generators step out due to a power system accident. It is.

  If an accident occurs in the power system, leaving it unattended not only causes damage to the system equipment, but can also make it difficult to maintain the operation of the entire system. Therefore, a protection relay system is installed in the power system for the purpose of quickly disconnecting the accident equipment from the system when a system fault occurs and reducing damage to the accident equipment and maintaining stable operation of the system.

  Protection relay systems are roughly classified into accident elimination relay systems and accident ripple prevention relay systems. The accident elimination relay system is installed for each system facility, and aims to quickly remove the accident section from the system. Moreover, even if the accident section is removed from the system, the influence of the accident may cause various abnormal phenomena such as system out-of-step, voltage abnormality, frequency abnormality, equipment overload, etc. for some reason and spread to the entire system.

  For such abnormal phenomena, the system itself is strengthened by expanding facilities such as power transmission lines and introducing control devices such as the power system stabilizing device PSS. By performing emergency control, abnormal phenomena are prevented from spreading to the entire system, and stable operation of the system is maintained. The accident ripple prevention relay system is also called a system stabilization device.

One of the installation purposes of the system stabilization device is a countermeasure for transient stability. FIG. 24 shows an example of a power system in which the generator G is connected to the main system (shown as an infinite bus in the figure) via the transmission line L. Normally, the generator G outputs an electrical output P _E and the generator as input mechanical input P _M, through the transmission line L is the transmission to the main system. Here, when an accident F occurs in the transmission line L, the accident is eliminated by opening the circuit breakers CB at both ends of the transmission line L by the accident removal relay. After that, if the conditions are met, the accident removal relay re-closes and returns to the state before the accident.

Figure 25 is a waveform diagram showing an example of a system of movement after the system fault occurs, Fig. 25 (a) shows a waveform of a case where an electrical output of the generator G power P _E is stabilized, 25 ( b) a waveform diagram in the case where the power P _E is an electrical output of the generator G becomes unstable, FIG 25 (c) is a waveform diagram showing an example of movement of an internal phase angle of the generator G.

In FIG. 25 (a), the accident before the power P _E is stable at a value corresponding to the mechanical output P _M, sagging is P _E in the accident occurrence time t0, the drop of the power P _E until the fault is cleared time t1 Continue. This time _TJ is called the accident duration. Return power P _E accident removal time t1, upset after when the influence of an accident is relatively minor accident removed converges over time becomes stable. On the other hand, as shown in FIG. 25 (b), when the accident duration _TJ is longer than the time t1 + Δt ′ of the accident duration _TJ ′ at which the stability limit is reached, that is, when the accident removal is time t1 + Δt, acceleration is increased, after the accident removed even unstable power P _E generator G is step-out.

  As shown in FIG. 25 (c), in the case of FIG. 25 (a), the internal phase angle change Δδa of the generator G temporarily increases from the accident removal time t1, but eventually converges. In the case of 25 (b), the internal phase angle change Δδb of the generator G increases and diverges from the accident removal time t1 + Δt, and synchronization with the main system cannot be maintained, causing the generator to step out. In this case, if the electric control for removing the accident is performed at the accident removal time t1 + Δt ′ of the stability limit, the internal phase angle change Δδb ′ of the generator G temporarily increases from the accident removal time t1 + Δt ′, but eventually Converge.

Here, the generator step-out and transient stability are theoretically explained by the relationship between the acceleration and deceleration energy using the P-δ curve, and the transient stability is determined by obtaining the area on the P-δ curve. The equal area method of performing is well known. Further, based on the equation of motion of the generator, it is also widely known that the acceleration energy of the generator can be calculated by integrating the drop in power P _E in the accident duration. A measure for stabilizing the generator step-out phenomenon is called a transient stability measure. Since this countermeasure for transient stability requires urgency, the control by the control system of the generator G such as the governor, the automatic voltage regulator AVR, and the power system stabilizer PSS is not in time.

  Therefore, the generator G is shut off to prevent the influence of the generator step-out from spreading to the main system side. This control requires high speed, and the control finish time from the occurrence of an accident to the breaker opening of the generator is on the order of several hundreds of milliseconds. Further, in FIG. 24, the generator G is drawn as one unit. However, it is normal that a plurality of generators are installed. The minimum generator generator is cut off and the generator is kept stable. Plan

  An off-line pre-computation method is one of the computation methods applied to the system stabilization device for transient stability countermeasures. FIG. 26 is a block diagram showing an example of a conventional pre-calculation type system stabilizing device, and FIG. 27 is a control for determining a necessary power control amount for generator shut-off (hereinafter referred to as power supply limitation or power control). It is explanatory drawing of an example of a table. Here, the control table is a table or graph that expresses the correlation of the required control amount when the power flow at a certain location in the power system is a parameter power flow. A mechanism that plays the same or similar role is essential. Here, as the parameter flow, it is common to select the output power value before the accident of the generator group to be stabilized.

  The configuration and function of a conventional off-line pre-calculation type system stabilization device will be described with reference to FIG. The system stabilizing device 1 includes an interface unit 10, a control table creation unit 4, an active power measurement unit 5, an accident condition detection unit 6, a control generator determination unit 7, and a control unit 8. .

  The generators G1 to G3 of the control target power plant of the power system are connected to the bus Bus via the circuit breakers CB1 to CB3, and are connected to the power transmission line L via the circuit breakers CB4 and CB5 from the bus Bus. Is connected to the main system of the infinite bus through circuit breakers CB6 and CB7. The voltage V and current I of the power system are input to the active power measuring means 5 and the accident condition detecting means 6, and the switching information C4 and C5 of the circuit breakers CB4 and CB5 and the operation information R of the protective relay device Ry are the accident condition detecting means. 6 is input.

  The interface means 10 is for setting control table information [Tab] obtained offline beforehand in the apparatus, and the control table information [Tab] taken into the apparatus via the interface means 10 is controlled. The data is input to the table creation means 4, arranged and processed into a form for use inside the apparatus, and stored in the control table creation means 4. The active power measuring means 5 measures the generator output active power P, which changes from moment to moment, using the amount of electricity (voltage V, current I) taken from the power system to be controlled in real time, and sends it to the control generator determination means 7. Output.

  The accident condition detection means 6 detects the occurrence of the accident and the aspect of the accident in real time when an accident occurs in the power system to be controlled. It outputs to the machine determination means 7. The accident condition detection means 6 includes an accident occurrence detector 6a for detecting occurrence of a system fault using the circuit breaker switching information C4 and C5 taken from the power system, the operation information R of the protection relay Ry, or the voltage V and the current I. And an accident aspect determination unit 6c that determines in which phase of the transmission line L an accident has occurred.

  The control generator determining means 7 includes a generator output active power P measured by the active power measuring means 5, an accident condition Fa detected by the accident condition detecting means 5, and a control table Tab stored by the control table creating means 4. Is used to determine a control generator that matches the tidal current state of the system and the accident condition Fa, and selects a control table Tab that matches the accident condition detected by the accident condition detection means 6. 7a, a pre-flow holding unit 7e that holds the pre-accident value of the generator output active power value P measured by the active power measuring means 5, and a control table Tab and a pre-flow holding unit 7e that are determined by the control table determining unit 7a. And a generator-generator determining unit 7c that determines the controller-controlled generator from the generator output active power value Px before the accident held in (1). The control means 8 outputs an electric control command to the electric power generator determined by the electric power generator determination means 7.

  The control table information [Tab] that is set and stored via the interface means 10 is a graph or table that correlates the necessary electric generator with the generator output active power value Px before the accident as shown in FIG. For example, in the example of FIG. 27, if the generator output active power value Px before the accident is between P1 and P2, the required control generator is 1G, and if it is between P2 and P3, 1G. In the case of 2 units of 2G and three units of 1G, 2G, and 3G in the case of P3 to P4, the necessary control generator can be determined from the generator output active power value Px before the accident.

  Here, as described above, since the stability varies depending on the accident condition, that is, the degree of influence of the accident, the control table Tab is set for each accident condition, that is, for each accident aspect such as a one-phase two-wire accident and a three-phase four-wire accident. Have it ready. With this configuration, an offline pre-calculation type system stabilization device can be realized using control table information [Tab] obtained in advance based on a prior offline simulation calculation.

  In order to obtain the control table Tab, the user needs to perform an enormous systematic phenomenon simulation analysis in advance. The stability of the system varies depending on the accident point and the aspect of the accident, and changes from time to time, season, system configuration change, future system change, etc., so it is necessary to obtain the control table Tab for each necessary case. Therefore, obtaining the control table Tab in advance is an important and indispensable work for operating the system stabilizing device, but requires a lot of labor and is a heavy burden on the user. Therefore, prior systematic phenomenon simulation analysis is usually performed by sampling characteristic system conditions, i.e., summer daytime and nighttime tidal current conditions. It is different from accident conditions. In this respect, system phenomenon simulation analysis performed in advance is called offline simulation, and this method is called offline pre-computation form.

  Here, since there are an infinite number of points that can become accident points in an actual system fault, in the system phenomenon simulation analysis when creating the control table, the conditions assuming a severe case in terms of stability, that is, the closest to the bus Subject to an accident. In addition, the accident duration also varies from the same time every time due to fluctuations in the circuit breaker opening time, etc., but in the simulation analysis, the main protection operation time of the accident elimination relay device is fixed at the worst value. Furthermore, in the step of obtaining the correlation between the parameter flow and the required control amount, the control amount that can be reliably stabilized as a result of the electric control is set as the required control amount. Therefore, the control table Tab that is determined based on these conditions covers all assumed system conditions and has more control contents so as not to cause a shortage of control amount. From the above, although the pre-computed system stabilization device 1 has the advantage of a fast operation time, it requires a lot of labor to create a control table, and does not reflect the actual accident phenomenon, so that it is more electrically controlled. become.

  Recently, there have been an increasing number of cases where an online pre-calculation system stabilization system for large-scale systems has been developed and introduced (for example, see Non-Patent Document 1). In an online pre-computation system, the computer automatically collects system information, creates system models, analyzes system phenomena simulations for assumed accident cases, and creates control tables at regular intervals. Although the user is relieved from the work of creating the control table in a human system, since it is a very expensive system for a large-scale system, it is difficult to apply it to a local generator system as shown in FIG. Further, the control amount error is basically the same as that of the conventional off-line pre-calculation apparatus.

  Although there is a tendency to focus on online pre-computation for large-scale systems as a recent need for system stabilization equipment for countermeasures against transient stability, there is still a need for simple pre-computation equipment for local generator systems. It is alive (see Non-Patent Document 2, for example). Furthermore, with regard to the latter, it is expected that a new system problem will appear as the number of distributed power sources increases in the future, so there is a possibility that it will become a new market in the future, and many demands can be expected.

  As described above, in the off-line pre-calculation type system stabilizing device for transient stability countermeasures, a great deal of labor is required to create a control table for obtaining the electric control amount, and a large amount of electric control is performed. As countermeasures, the grid information is taken and the current grid model is created at all times, the fault condition is detected in real time after the accident occurs, the stability is determined by the transient stability calculation, and in the case of an unstable case In addition, a method of performing transient control by performing transient stability calculation for determining a controlled generator is considered (for example, see Patent Document 1). This method can be referred to as an online post-calculation type as compared to the conventional offline pre-calculation type. According to this, stability determination and generator control that reflect actual accident conditions that occur in actual system conditions can be performed, which is a promising method for solving the problems of conventional system stabilization devices.

Japanese Patent No. 3350265

IEEJ Technical Report No.801 “Relay Technology for System Step-out / Accident Prevention”, The Institute of Electrical Engineers of Japan, October 2000, p5-6, p52-56, p61-63 Nittame Yuzo, "Application of Power System Technology Calculation", Denki Shoin, June 1, 1981, p357-363

  However, since it is necessary to execute the transient stability calculation at a speed higher than the actual phenomenon, the feasibility at this stage is poor. Of the ones in Patent Document 1, the system model creation, the analysis condition setting, and the transient stability calculation can be sufficiently realized if they are always executed at a constant cycle. In addition, it is possible to create a control table by automatically calculating the transient stability when an accident that is assumed in actual system conditions occurs.

  An object of the present invention is to provide a highly accurate pre-calculation type system stabilization device that does not require offline simulation work by a human system and can reflect actual system conditions and accident conditions in the calculation.

  The system stabilizing device of the present invention collects the connection state of the power system and the power supply and demand state at regular intervals as system information, and based on the collected system information and pre-stored system facility data, An analysis condition for setting a plurality of analysis conditions by changing an accident condition based on an analysis system model created by the system model creation means and a system model creation means for creating an analysis system model representing the current power flow state Transient stability calculation is performed while changing a partial condition as a parameter for each analysis condition set by the setting means and the analysis condition setting means, and together with the transient stability calculation, the generator output active power before the accident and sometimes A stability determination amount obtained by time-integrating the difference from the momentarily changing generator output active power from the accident occurrence time to the accident removal time is calculated. When it is determined that the system phenomenon obtained by the stability calculation is unstable and determined to be unstable, the stability determination amount is determined as a stability limit value, and the accident removal time which is one of the conditions of the transient stability calculation , The transient stability calculation by changing the combination of electric generators with the electric control implementation time, and determining the optimum electric generator combination that can stabilize the instability phenomenon and determining it as the necessary electric generator, Control table creation means for creating and storing a control table that associates the stability limit value with the required electric power generator for each analysis condition, and power generation that changes from time to time using the amount of electricity taken from the power system An active power measuring means for measuring the machine output active power in real time, and an accident condition detecting means for detecting the occurrence of the accident, the accident removal and the accident aspect in real time when an accident occurs in the power system; A control table that matches the accident condition detected by the accident condition detection means is determined from the control tables for each analysis condition created by the control table creation means, and the generator output effective measured by the active power measurement means is determined. The power is input, the stability determination amount is calculated in real time by the same calculation as the control table creation means, and the necessary power corresponding to the stability determination amount calculated in real time with reference to the determined control table. A power generator determining means for determining a power generator; and a control means for stabilizing the power system by disconnecting the power generator determined by the power generator determining means from the power system. It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, the offline simulation operation | work by a human system is unnecessary, and the highly accurate pre-calculation type | system | group stabilization apparatus which can reflect an actual system | strain condition and accident condition in a calculation can be provided.

The block block diagram of the system | strain stabilization apparatus concerning the 1st Embodiment of this invention. Explanatory drawing which shows an example of the control table in embodiment of this invention. The flowchart which shows an example of the processing content of the control table preparation means in the 1st Embodiment of this invention. The flowchart which shows the processing content of the accident condition detection means in the 1st Embodiment of this invention. The flowchart which shows the processing content of the control generator determination means in the 1st Embodiment of this invention. The flowchart which shows another example of the processing content of the control table preparation means in the 1st Embodiment of this invention. Waveform diagram showing an example of movement of the power which the power P _E of the electrical output of the generator is less than the mechanical input P _M in the first embodiment after an accident removed in the form of the present invention. Flow showing an example of the processing content of the electronically controlled generator determining unit 7 when the electrical output of the power P _E of the generator is less than the mechanical input P _M after the first form in accidents removal of the present invention Figure. Explanatory drawing which shows an example of the control table which performs electric control when the stability limit value is reached in the middle of calculation of the stability determination amount in the first embodiment of the present invention. The flowchart of the control table preparation means in the case of performing electronic control when the stability limit value is reached in the middle of calculation of the stability determination amount in the first embodiment of the present invention. The flowchart of the accident condition detection means in the case of carrying out electric control when the stability limit value is reached in the middle of calculation of the stability determination amount in the first embodiment of the present invention. The flowchart of the electric generator determination means 7 in the case of carrying out electric control when the stability limit value is reached in the middle of calculation of the stability determination amount in the first embodiment of the present invention. The block block diagram of the system | strain stabilization apparatus concerning the 2nd Embodiment of this invention. The wave form diagram which shows an example of the motion of the electric power at the time of the backup protection operation | movement in the 2nd Embodiment of this invention. The flowchart which shows an example of the processing content of the accident condition detection means of the 2nd Embodiment of this invention. The flowchart which shows an example of the processing content of the control generator determination means 7 of the 2nd Embodiment of this invention. The block block diagram of the system | strain stabilization apparatus concerning the 3rd Embodiment of this invention. The flowchart which shows an example of the processing content of the accident condition detection means of the 3rd Embodiment of this invention. The flowchart which shows an example of the processing content of the control generator determination means of the 3rd Embodiment of this invention. The block block diagram of the system | strain stabilization apparatus concerning the 4th Embodiment of this invention. The flowchart which shows an example of the processing content of the control generator determination means 7 in the 4th Embodiment of this invention. The block block diagram of the system | strain stabilization apparatus concerning the 5th Embodiment of this invention. The block block diagram of the system | strain stabilization apparatus concerning the 6th Embodiment of this invention. The system diagram which shows an example of 1 machine infinite system. The wave form diagram which shows an example of the motion of the system | strain after a system | strain accident occurrence. The block diagram which shows the structure of the conventional system | strain stabilization apparatus. Explanatory drawing of an example of the control table for the electric control amount calculation of the conventional system | strain stabilization apparatus.

Embodiments of the present invention will be described below. First, the basic concept of the present invention will be described. In Figure 24, as described above, the one-machine infinite system, the generator G was generator being connected to the main system through the transmission line L (infinite bus), the mechanical input P _M as an input electrical The target output _PE is transmitted to the main system via the transmission line L. Here, a system phenomenon when an accident occurs in the transmission line L will be described with reference to FIG. Depending on the degree of influence of the system fault, there may be a stable case as shown in FIG. 25 (a) or an unstable case as shown in FIG. 25 (b). In the system fault, when the accident aspect, that is, the combination of the phase of the accident occurrence, the accident point and the fault point impedance are the same conditions, the time integration of the power drop from the accident occurrence to the accident removal (FIG. 25 (a) and The transient stability of the system is determined by the area of the hatched portion in FIG.

Here, when the accident duration _TJ becomes longer than the stable case (accident removal time t1) in FIG. 25 (a), a limit value exists immediately before reaching the unstable region in FIG. 25 (b). . This limit value is referred to as a stability limit value S _limit . The stability limit value S _limit is expressed by equation (1), and the relationship between the accident removal time differences is expressed by equation (2).

[Equation 2]
0 (stable) <Δt ′ (stability limit) <Δt (unstable) (2)
Where P _M : mechanical input of the generator G, P _E : electrical output of the generator G, t 0: accident occurrence time, t 1: accident removal time in the stable case shown in FIG. 25A, t 1 + Δt: accident Accident removal time when removal is delayed by Δt, t1 + Δt ′: Accident removal time in the stable limit case (accident removal delay = Δt ′).

The stability limit value S _limit can be obtained in advance by offline simulation. It is also possible to obtain a necessary electric generator for stabilizing the unstable phenomenon when the stability limit value S _limit is exceeded. Therefore, stable if indeed system fault occurs, by calculating the time integral S slump of the generator output P _E in accidents continues in real time, to advance compared stability limit value S _limit the magnitude had been determined The degree can be judged. Here, the integration S is referred to as a stability determination amount. The stability determination amount S is expressed by equation (3), and can be determined as an unstable case when the magnitude relationship of equation (4) is established.

[Equation 4]
S> S _limit (4)
Furthermore, when it is determined that the case is unstable, the unstable phenomenon can be stabilized by shutting off the necessary power generator that has been obtained in advance. Further, the necessary electric generator can be obtained by preparing a control table Tab as in the conventional method.

  FIG. 2 is an explanatory diagram showing an example of the control table Tab in the embodiment of the present invention. This shows the correlation between the stability determination amount S and the necessary electric generator, and the necessary electric control amount for stabilizing the phenomenon increases as the accident removal time is delayed and the accident duration time is increased. Showing the relationship. In the example of FIG. 2, the required electric generator is one unit of 1G when the stability determination amount S is between S1 (the stability limit value at the accident removal time t1) and S2 (the stability limit value at the accident removal time t2). When the stability judgment amount is between S2 (stability limit value at t2) to S3 (stability limit value at t3), the required power generators are 1G and 2G, and the stability judgment amount is S3 (at t3) The required electric generators are 1G, 2G, and 3G between S4 (stable limit value) to S4 (stable limit value at t4). In the embodiment of the present invention, the user can not only obtain the control table Tab by an off-line simulation in advance, but also can incorporate a part of the configuration shown in Patent Document 1 and automatically execute it inside the system stabilizing device. It is.

  The control table Tab needs to be provided for each assumed accident condition, but the accident condition has an accident aspect, an accident point and an accident point impedance, and an accident duration, and these combinations exist strictly infinitely. . In view of this, the case classification of actual assumed accident conditions and parameter selection for determining the stability determination amount that is the horizontal axis of the control table Tab will be summarized below.

While the accident continues, all of these accident conditions appear as a drop in power, so the difference in each condition can be reflected by calculating the stability limit value S _limit and the stability determination amount S. However, since only the accident aspect greatly affects the stability after the accident is removed, the control table Tab is provided for each assumed accident aspect. For parameter selection for determining the stability determination amount S that is the horizontal axis of the control table Tab, the method of selecting the accident duration used for the definition and explanation of the above stability limit value S _limit , the accident point, and the accident There are also a method of selecting a point impedance, or a method of combining a plurality of these conditions. Based on the above concept, it is possible to provide a new system stabilization device that overcomes the disadvantages of the conventional offline pre-computation system stabilization system.

  FIG. 1 is a block configuration diagram of a system stabilizing apparatus 1 according to the first embodiment of the present invention. The system stabilizing device 1 includes a system model creating means 2, an analysis condition setting means 3, a control table creating means 4, an active power measuring means 5, an accident condition detecting means 6, an electric power generator determining means 7, And control means 8. The same elements as those in the conventional example shown in FIG.

  The system model creation means 2 is equivalent to that of Patent Document 1, and is periodically executed in advance. In other words, the system model creation means 2 includes the connection state of the power system transmitted from each substation or power plant in the power system (for example, the open / close state of the circuit breaker or disconnector), and the power supply / demand state (generator System status collection unit 2a that collects the output and effective load and reactive power) as system information, information storage unit 2b that stores the system information collected by the system status collection unit 2a, the impedance of the transmission line L and the generator Are stored in advance as system equipment data, using the system information in the information storage section 2b, the impedance of the power transmission line in the system equipment storage section 2c, and the generator constants, The system model creation unit 2d creates the system model Md for analysis.

  The analysis condition setting unit 3 includes a system model storage unit 3a that stores the system model Md for analysis created by the system model creation unit 2, and an operation condition storage that stores in advance various operation constraint conditions of the generator to be controlled. Using the analysis system model stored in the unit 3b, the system model storage unit 3a and the operation condition storage unit 3b, the operation constraint condition of the power generation target generator, and the accident condition assumed in the stabilization target system, It comprises an analysis condition setting unit 3c that sets a plurality of analysis conditions At by changing the combination of electric generators.

  The analysis condition setting means 3 is functionally similar to that of Patent Document 1, but is different from that of Patent Document 1 in that it is periodically executed in advance and an accident assumed in the stabilization target system. The necessary case is set from the combination of conditions, that is, the accident aspect, the accident point, the accident point impedance, and the accident duration.

  Here, there are infinite variations of the accident point and the fault point impedance. Therefore, as a realistic case setting, an assumed pattern is set for the accident aspect, and the accident point and the impedance are reflected in the stability limit value and the stability determination amount, so that one representative case (for example, phenomenologically) As strict conditions, it is limited to the bus near-end accident at the power plant to be controlled and the impedance at the accident point = 0). Each accident condition set here is used as a condition for determining the control table in the control table creation means 4 described later, and the accident duration is used as a parameter for determining the stability determination amount S that becomes the horizontal axis of the control table Tab. Here, as another method, the accident duration is set as one representative case, and the accident point and the accident point impedance are also parameters for determining the stability judgment amount, and the accident duration, the accident point and the accident point impedance are parameters. The method used as can be considered. A configuration in which the system model creation means 2 has a system contraction unit as in Patent Document 1 is also conceivable.

The control table creation means 4 includes an analysis condition storage unit 4a, a transient stability calculation unit 4b, a stability determination unit 4c, a stability limit value storage unit 4d, a telecommunication generator selection unit 4e, telecommunication generation The stability determination amount S and the necessary electric generator are configured using the analysis system model Md obtained by the system model creation means 2 and the analysis condition At obtained by the analysis condition setting means 3. Is created for each analysis condition At. These series of functions are the same as those in the stability determination means and the electric generator determination means in Patent Document 1, but unlike in Patent Document 1, the system model creation means 2 and analysis condition setting It is periodically executed in advance with the means 3 and for all analysis conditions At. Furthermore, the transient stability calculation unit 4c to add the function of determining the stability limit value S _limit for each analysis condition, where the determined the stability limit value S _limit stored in stability limit value storage unit 4d. The correlation between the stability limit value S _limit for each analysis condition At obtained by the control table creation means 4 and the electric generator is the control table Tab.

  The active power measuring means 5 is for measuring the active power value P of the generator output in real time. The accident condition detection means 6 includes an accident occurrence detection unit 6a, an accident removal detection unit 6b, and an accident aspect determination unit 6c. The detection of accident occurrence and accident removal and the accident aspect of an accident that actually occurred in the system. Judgment is made and the accident condition Fa is output.

  The control generator determination means 7 includes a control table determination unit 7a, a stability determination amount calculation unit 4b, and a control generator determination unit 7c. The control table determination unit 7a selects a control table Tab that matches the actual accident condition Fa from the control table for each analysis condition. The stability determination amount calculation unit 7b calculates the area of the falling portion of the generator output active power P measured in real time by the active power measuring means 5 during the accident, that is, the stability determination amount S. The control generator determination unit 7c determines a necessary control generator from the control table Tab determined by the control table determination unit 7a and the stability determination amount S calculated by the stability determination amount calculation unit 7b. The control means 8 outputs an electric control command to the electric power generator determined by the electric power generator determination means 7.

  First, an overview of the overall function flow will be described. The system model creation means 2, the analysis condition setting means 3, and the control table creation means 4 are necessary in the case of instability and stability determination for each accident point and accident aspect when an accident occurs in the actual system at that time. The control table is created by calculating the transient stability to obtain the electric control amount. A series of these processes is always executed at a constant cycle.

  The active power measuring means 5 measures the generator output active power that changes every moment in real time. The accident condition detection means 6 is always executed in real time, and detects the occurrence, removal, and accident aspect when a system fault occurs in the real system. The electric power generator determination means 7 and the control means 8 are activated when an accident occurrence is detected by the accident condition detection means 6, and implements appropriate electric control according to the control table for the accident to be controlled.

  FIG. 3 is a flowchart showing an example of the processing contents of the control table creation means 4 in the first embodiment of the present invention. In step (S1), the system model created by the system model creating means is fetched. Next, in step (S2), the analysis condition created by the analysis condition setting means is fetched. Next, in step (S3), initial analysis conditions are set as initial settings for repeatedly determining the transient stability for a plurality of analysis conditions. Next, in step (S4), the minimum value of the accident removal time is set as an initial setting for obtaining the stability limit value while changing the accident duration for each analysis condition. Next, in step (S5), the electric power generator is set in a state without selection which becomes an initial state. In the above steps, the initial settings for the first analysis condition selected in step (S3) are complete, so in step (S6), these are stored as analysis conditions.

  In step (S7), transient stability calculation is performed for the analysis conditions stored in step (S6). In this step (S7), the stability determination amount, which is a feature of the present invention, is also calculated.

  In step (S8), as a result of the transient stability calculation, it is confirmed whether it is stable or unstable, and the process branches. If stable, the process branches to step (S10). If unstable, the process branches to step (S8a) to determine whether all generators are selected. If not all generators are selected, the process proceeds to step (S9).

  In other words, in the case of instability, it is necessary to obtain a telecommunication generator necessary for stabilizing the instability phenomenon. Therefore, in step (S9), one electric generator is added, and the process returns to step (S6). With this flow configuration, a necessary electric generator capable of stabilizing the unstable phenomenon can be obtained. If the phenomenon cannot be stabilized even if all the generators to be controlled are selected as control generators, it is determined in step (S8a) whether or not all the generators are selected, and the process branches to step (S10). .

  In the above steps, the stability determination amount and the necessary electric generator are obtained for one analysis condition and the accident removal time. Therefore, in step (S10), the obtained stability determination amount and the necessary electric generator are controlled by the control table. To remember.

  Next, in step (S11) and step (S12), a value obtained by adding the step time Δt to the accident removal time t1 is set as a new accident removal time t2, and the process returns to step (S5). Thereafter, using the newly set accident removal time t2 as a new analysis condition, transient stability calculation, stability determination, and necessary electric generator selection are performed. If the accident removal time setting exceeds the predetermined maximum time, it means that all of the assumed range of the accident removal time has been processed, so the process branches to step (13) and proceeds to the processing for the next analysis condition. .

  In step (S13) and step (S14), it is determined whether or not the process has been completed for all analysis conditions. If there is an analysis condition that has not been processed yet, the next analysis condition is selected, and step Returning to (S4), the same processing is repeated. When the processing is completed for all the analysis conditions, the processing of the control table creating means 4, that is, the control table relating the stability limit value and the necessary power control amount for each analysis condition is completed.

  FIG. 4 is a flowchart showing the processing contents of the accident condition detection means 6 in the first embodiment of the present invention. In step (S1) and step (S2), the transition of the generator output active power value measured by the active power measuring means 5 is observed, and if a drop is detected, it is determined that an accident has occurred and stored as an accident detection. To do. In step (S3) and step (S4), the transition of the generator output active power value measured by the active power measuring means 5 is observed, and it is determined that the accident has been removed when the return of the drop is detected. Store as removal detection. Here, as other realization methods of the accident detection and the accident removal detection, a method of judging by looking at the on / off change of the transmission line using the circuit breaker open / close state of the transmission line L, and the operation information R of the protection relay Ry are used. There is also a method to detect.

  Next, in step (S5) and subsequent steps, accident phase detection is performed to detect in which phase of the transmission line L the accident has occurred. In step (S5), current amplitude values are measured for all six phases of two transmission lines and three phases. Here, since it can be determined that a phase having a current amplitude value less than a certain value is interrupted by the protection relay Ry due to the occurrence of an accident, a phase having a current amplitude value less than a certain value is determined in step (S7) and step (S8). Remember as accident phase. Step (S6) and step (S9) are steps for controlling repetition for all six phases of the transmission line, and the accident phase detection is determined and stored for all six phases of the transmission line. In step (S9), it is determined whether or not the repetition is completed. If the repetition is not completed, the process returns to step (S6), and if the repetition is completed, the process is terminated.

  In the above description, the accident phase detection is performed in step (S7) by paying attention to the fact that the amplitude value of each phase of the transmission line is less than a certain value. The determination may be made using the state, or may be made using the operation information R of the protection relay Ry.

  FIG. 5 is a flowchart showing the processing contents of the control generator determination means 7 in the first embodiment of the present invention. Step (S1) corresponds to the start determination part of the control generator determining means 7, and the subsequent processing is executed when an accident is detected by the accident condition detecting means 6.

  In step (S2), the accident mode (for example, one-phase one-line accident, three-phase) indicated by the accident phase detected by the accident condition detection unit 6 from the control table of each analysis condition obtained by the control table creation unit 4 Select the control table that matches the 4-wire accident, etc.). In step (S3) and step (S4), the stability determination amount is calculated until accident removal is detected. As described above, the stability determination amount is the time integration of the falling portion of the active power during the accident, but since there is a time resolution ΔT of software processing, it is actually performed with a discrete area sum. In step (S5), using the control table selected in step (S2) and the stability determination amount S when the accident is removed calculated in steps (S3) and (S4), the necessary electric generator To decide.

  This makes it possible to overcome the disadvantages of conventional pre-computation type system stabilization devices, eliminates the need for prior offline simulation by human systems, and allows high-accuracy system stabilization devices to reflect actual system conditions and actual accident conditions in calculations. Can provide.

  In the above description, the control table creation means 4 uses the accident elimination time t1 as the electric control execution timing in the transient stability calculation for obtaining the necessary electric generator, but after the electric control command is output from the system stabilizing device Considering that there is a time delay until the breaker of the generator is actually opened, the timing of the electric control in the transient stability calculation to obtain the required electric generator is determined from the control command output. A control table set in consideration of the finishing time up to the pole may be created. That is, there is a time delay from the output of the electric control command from the system stabilizing device 1 to the actual opening of the circuit breaker of the generator. Therefore, the control timing is corrected in consideration of the delay time, and the analysis condition is used in the transient stability calculation for determining the control generator.

  FIG. 6 is a flowchart showing another example of the processing contents of the control table creation means 4 in the first exemplary embodiment of the present invention. Compared to the flowchart shown in FIG. 3, in step (S9), the time τ from the control command output to the circuit breaker opening is added to the generator control timing, and the control finish timing is designated as the accident removal time t1 + τ. It is designed to perform transient stability calculation for determining electric generators. Since the other steps are the same as those in FIG. 3, the same steps are denoted by the same reference numerals, and redundant description is omitted. Thereby, it is possible to correct the delay of the electric control execution timing, which was not considered in FIG. 3, and to provide a more accurate system stabilizing device.

  In the above explanation, the stability judgment amount calculation is the time integration of the drop in active power from the occurrence of the accident to the removal of the accident, but the generator output active power immediately after the accident removal is the effective output of the generator before the accident. When the power is lower than the power, the calculation of the stability determination amount may be continued from the time when the accident removal is detected until the time when the generator output active power value returns to the generator output active power before the accident. The calculation of the stability determination amount is performed by both the control table creation means 4 and the electric power generator determination means 7.

  That is, depending on the accident removal timing, the return of active power due to the accident removal is low, and the generator may accelerate even after the accident removal. In this case, the generator continues to accelerate until the active power after the accident is removed returns to the value before the accident, so the calculation of the stability judgment amount continues until the active power returns to the value before the accident after the accident is removed. To do.

7, the electrical output of the power P _E of the generator after the fault is cleared is a waveform diagram showing an example of motion of power smaller than the mechanical input P _M. This is an accident in the drop in active power fault removal is performed in fault removal time t1 is restored, a case active power value P _E does not return to a value P _M before the accident. In this case, the acceleration of the generator also continued after the fault is cleared, until time t2 when the P E ₌ P _M. Therefore, in this case, the calculation of the stability determination amount continues even after the accident is removed, and the area of the hatched portion in FIG.

Figure 8 is a flowchart showing an example of processing contents of the electronically controlled generator determining unit 7 when the electrical output of the power P _E of the generator is less than the mechanical input P _M after the fault is cleared. To the flowchart shown in FIG. 5, by adding steps (S4a), the timing of active power calculation of stability determination amount is returned to the value before the accident, i.e. so as to continue until P _{E =} P _M Yes. Since the other steps are the same as those in FIG. 3, the same steps are denoted by the same reference numerals, and redundant description is omitted. Since the calculation of the stability determination amount is also performed in the transient stability calculation of the control table creation means 4, a step equivalent to step (S4a) is added in the same manner as described above. Thereby, the system stabilization apparatus applicable also to the case where a generator accelerates after accident removal can be provided.

In the above description, the electric control is performed after detecting the accident removal, but the electric control is sequentially performed when the stability determination value S reaches the stability limit value S _limit in the process of increasing with time. You may be able to do it. That is, even if it is found that the stability limit value has already been exceeded during the calculation of the stability judgment amount during the accident, when the control is performed at the timing when the calculation of the stability judgment amount ends (accident elimination timing) The implementation of the electric control system will wait until the accident is removed. Here, if the timing of implementation of electric control can be advanced, the acceleration energy of the generator is also lost due to electric control, so the phenomenon goes in a stable direction. As a result, there is a possibility that the phenomenon can be stabilized with a small amount of required electric control. Therefore, electric control can be performed when the stability limit value is reached during the calculation of the stability determination amount.

Therefore, the control table creation unit 4 integrates the active power over time during the accident so that the electric control can be sequentially performed when the stability determination value S reaches the stability limit value S _limit in the process of increasing over time. A control table is created for sequentially controlling the generators when the stability determination amount calculated from moment to moment reaches the stability limit value. The accident condition detection means 6 can detect the accident phase while the accident continues, and the electric generator determination means 7 refers to the control table when the stability determination value reaches the stability limit value. The machine is determined and the control means 8 is executed.

  FIG. 9 is an explanatory diagram illustrating an example of a control table that performs power control when the stability limit value is reached during the calculation of the stability determination amount. In FIG. 9, a control table (thick line) that implements electric control at the timing when the calculation of the stability determination amount shown in FIG. 2 ends (accident removal timing) is shown superimposed.

Control table to implement the electrical control calculation is completed timing of the indicated stability determination amount in FIG. 2 (fault removal timing) is the stability determination amount S1, S2, S3, S4, ... it is stability limit value S _limit becomes, When the stability determination amount S is S1 to S2, the required power generator is 1G, when the stability determination amount S is S2 to S3, two units 1G and 2G, and the stability determination amount S is S3 to S3. In the case of S4, the correlation of 3 units 1G, 2G and 3G,... Is shown.

On the other hand, in the control table that performs electric control when the stability limit value S _limit is reached during the calculation of the stability determination amount, 1G is controlled and reaches S2 ′ when the stability determination amount S reaches S1. At that time, 2G is added, and when S3 'is reached, 3G is added, and so on. In the control table in which the control is performed when the stability limit value S _limit is reached during the calculation of the stability determination amount, the stability determination amount S becomes the stability limit values S1, S2 ′, S3 ′, without waiting for the accident removal detection. When it reaches ..., the electric control will be implemented sequentially.

  As a result, the stability limit value S2 increases to S2 'and the stability limit value S3 increases to S3', whereby the stability limit value of the control table can be increased as a whole. As a result, it is possible to reduce the necessary control amount even when the stability determination amount S is the same.

  FIG. 10 is a flowchart of the control table creation means 4 when the electronic control is performed when the stability limit value is reached during the calculation of the stability determination amount in the first embodiment of the present invention. This is based on the flow chart of the control table creation means 4 in FIG. 3, and the return position of the processing flow after step (S12) is changed from step (S5) to step (S6). The other parts are the same as those in FIG.

  By doing so, the control generator selection in the region where the stability determination amount obtained previously is small is reflected as the analysis condition for the transient stability calculation and the necessary control generator selection in the next new accident duration. can do. As a result, it is possible to obtain a control table for sequentially performing additional electric control when the stability limit value is reached.

  FIG. 11 is a flowchart of the accident condition detection means 6 when the electronic control is performed when the stability limit value is reached in the middle of calculation of the stability determination amount in the first embodiment of the present invention. Based on the flowchart of the accident condition detection means 6 of FIG. 4, the accident phase determination is changed in step (S7) so as to be determined based on whether the current amplitude value is a certain value or more. By determining the current amplitude value to be greater than or equal to a certain value, the accident phase can be detected from the current during the accident, so that the accident phase determination during the accident can be performed. The other parts are the same as those in FIG.

  FIG. 12 is a flowchart of the electric generator determining means 7 when electric control is performed when the stability limit value is reached during the calculation of the stability determination amount in the first embodiment of the present invention. This is based on the flow chart of the control generator determination means of FIG. 5, and is configured so that the control generator determination and control execution can be performed when the stability determination amount reaches the stability limit value. . That is, in step (S3a), it is determined whether or not the stability determination amount has reached the stability limit value. If the stability determination value has not been reached, the calculation of the stability determination amount is continued. When the stability determination amount reaches the stability limit value, the control generator 8 determines the necessary control generator using the control table in the control generator determination unit 7c (step S5), and the power generation selected by the control means 8 An electric control command is output to the machine (step S6). Thereby, it is possible to reduce the number of necessary electric generators by advancing the electric control execution timing.

  Next, a second embodiment of the present invention will be described. FIG. 13 is a block diagram of a system stabilizing apparatus according to the second embodiment of the present invention. In the second embodiment, a main protection operation detection unit 6d is added to the accident condition detection means 6 with respect to the first embodiment shown in FIG. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The control table creation means 4 also creates a control table corresponding to the main protection operation failure / reserve protection operation, and the control generator determination means 7 is the main protection action detection unit of the accident condition detection means 6. When the main protection operation is detected in 6d and the accident continues, the control table corresponding to the main protection operation failure / reserve protection operation is determined.

  FIG. 14 is a waveform diagram showing an example of the movement of power during the backup protection operation in the second embodiment of the present invention. There is a case where an accident occurs at time t0 and the main protection operates at time t1 to remove the accident, but the circuit breaker cannot be completely removed because the circuit breaker of the transmission line L cannot be opened for some reason. In this case, the backup protection is activated at the timing of time t2, and the accident is removed. The rear protection operation is time coordinated with the main protection so that it operates for the first time in the case of the main protection operation failure, and the operation timing is set late (about several hundred ms from the occurrence of the accident).

  As shown in FIG. 14, the power drop is restored by the accident removal by the main protection operation at the time t <b> 1, but the state where the electric power does not return completely continues because the accident remains. Thereafter, the accident is completely removed by the accident removal by the protection operation at the time t2, and the power is restored. In this case, although the area of the hatched portion in FIG. 14 is the acceleration energy of the generator, it is larger than the area at the time of the main protection operation success, so the main protection even if the accident itself is minor and stable There may be an unstable case due to operation failure.

  In the second embodiment of the present invention, the main protection operation detection unit 6d is added to the accident condition detection means 6 to detect the main protection operation timing, and the control generator determination means 7 further detects the main protection operation timing. The main protection operation failure and the accident continuation phase are recognized from the presence / absence of the accident phase and its state, and the necessary electric generator is determined by selecting a control table that matches these conditions.

  Naturally, since it is necessary to prepare a control table in the case of the main protection operation failure case in advance, the analysis condition setting means 3 uses the pattern of each accident continuation phase after the main protection operation failure as the analysis condition At. Expect. The control table creation means 4 also creates a control table for each case of the main protection operation failure predicted by the analysis condition setting means 3 by performing transient stability calculation and selection of necessary electric generators.

  FIG. 15 is a flowchart showing an example of the processing contents of the accident condition detection means 6 according to the second embodiment of this invention. This is obtained by adding steps (S10) and (S11) to detect the main protection operation with respect to the flowchart of the accident condition detecting means 6 of the first embodiment shown in FIG. is there. Since others are the same as those in FIG. 4, the duplicate description of the same steps is omitted.

  The main protection operation is performed from the occurrence of the accident to the opening of the transmission line breaker in about 70 ms. Focusing on this point, in step (S10) and step (S11), an attempt is made to determine the main protection operation based on the passage of time from the detection of the accident. As another method, there is a method of detecting the main protection operation using the power line breaker switching information or the protection relay operation information.

  FIG. 16 is a flowchart showing an example of the processing contents of the control generator determination means 7 according to the second embodiment of this invention. This is because the step (S1a), step (S1b) and step (S2a) are added to the flow chart of the control generator determining means 7 of the first embodiment shown in FIG. The subsequent accident continuation state is determined, and a control table that matches the conditions is selected. Since others are the same as those in FIG. 5, the duplicate description of the same steps is omitted.

  In step (S1a), the process branches depending on the presence or absence of the main protection operation. When there is no main protection operation, a control table that matches the accident aspect is selected in step (S2) as in the first embodiment shown in FIG. On the other hand, if there is a main protection operation, the process branches to step (S1b), and the process is further branched depending on whether the accident continues. If there is no accident continuation, the main protection operation is successful, so the process returns to step (S2). If there is an accident continuation, the control table matches the combination of the main protection operation failure and the accident aspect in step (S2a). Then, the process proceeds to the execution of the control generator determination process in step (S5).

  In the case of failure of the main protection operation, since the accident remains after the main protection operation, implementation of electric control is urgent. Therefore, after determining the failure of the main protection operation and determining an appropriate control table in step (S1b) and step (S2a), the control generator is determined immediately in step (S5). The control means 8 can output an immediate electric control command. Thereby, the system stabilization apparatus which can respond also to a main protection operation failure and a back-end protection operation case can be provided.

Here, it can be handled by constant at the value before the accident the mechanical input P _M by the calculation period of the stability limit value and the stability determination amount and short the accident to the main protective operation, back-up the mechanical input P _M is controlled during the time course of up protection operation by the generator control system, such as AVR and governor changes, can not be treated as a constant value of mechanical input P _M accident previous value . Therefore, by reflecting the real-time estimated or measured calculation of the stability determination amount of time course of mechanical input P _M, the calculation period of the stability limit value and the stability determination amount from the accident to backup protection operation enlarged It is also feasible to do so.

  Next, a third embodiment of the present invention will be described. FIG. 17 is a block diagram of a system stabilizing apparatus according to the third embodiment of the present invention. In the third embodiment, an accident point locating unit 6e is added to the accident condition detecting means 6 with respect to the first embodiment shown in FIG. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The control table creating means 4 also creates a control table in which a plurality of accident points are changed as the analysis condition At, and the electric generator determining means 7 is an accident point locating unit 6e of the accident condition detecting means 6. When an accident point is determined, a control table is determined that is closest to the determined accident point and has strict conditions for stability.

  In the first embodiment, the accident point assumption of the analysis condition setting means 3 is set to a phenomenologically severe condition, that is, the closest point of the power plant to be controlled of the transmission line L, and between the actual system accident conditions. Even if there is a shift in the accident point, it is assumed that it is reflected in the area where the active power falls during the accident, that is, the stability determination amount S. Therefore, in order to further increase the accuracy, the accident point locating unit 6e is provided in the third embodiment so that the actual accident conditions are faithfully reflected in the stabilization calculation. Naturally, since it is necessary to obtain in advance the analysis conditions in which the accident point and the accident point impedance are changed and the control table corresponding to the analysis conditions, the analysis condition setting means 3 and the control table creation means 4 involve extension of the assumed cases. .

  FIG. 18 is a flowchart showing an example of processing contents of the accident condition detection means 6 according to the third exemplary embodiment of the present invention. This is obtained by adding steps (S10) and (S11) to the flowchart of the accident condition detecting means 6 of the first embodiment shown in FIG. Since others are the same as those in FIG. 4, the duplicate description of the same steps is omitted.

  In these steps (S10) and (S11), an accident point location calculation based on impedance calculation is performed from the voltage and current during the accident of the transmission line, and the calculation result, that is, the distance of the accident point and the accident point impedance are stored.

  FIG. 19 is a flowchart showing an example of the processing contents of the control generator determining unit 7 according to the third embodiment of this invention. This is because when the control table that matches the actual accident condition is selected in step (S2) with respect to the flow chart of the control generator determining means 7 of the first embodiment shown in FIG. In addition to the accident aspect which is the condition in the first embodiment, the accident point mark calculation result is also used as a condition.

  In an actual accident, there are infinite combinations of the location of the accident point and the accident impedance, but the analysis conditions for creating the control table are limited, so there is a control table that perfectly matches the actual accident conditions. It is actually not. In such a case, the control table corresponding to the condition that is closest to the accident condition and that is severe in terms of stability is selected.

  As a result, in the first embodiment, the accident point is divided and treated as a near-end accident, which is a severe condition for stability, and the actual accident condition, that is, the position of the accident point and the accident point impedance are reflected. Thus, more accurate control can be performed.

  Next, a fourth embodiment of the present invention will be described. FIG. 20 is a block diagram of a system stabilizing apparatus according to the fourth embodiment of the present invention. This fourth embodiment is different from the first embodiment shown in FIG. 1 in that the active power measuring means 5 is removed and a stable limit accident is used instead of the stable limit value storage unit 4d of the control table creating means 4. A duration storage unit 4g is provided, and an accident duration measurement unit 7d is provided instead of the stability determination amount calculation unit 7b of the control generator determination means 7. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The severity of the accident can be measured by the size of the area where the active power drops during the accident. Here, the drop in active power during an accident is determined by the accident condition, that is, the accident aspect, the accident point, and the accident point impedance. Therefore, if the accident duration can be measured, the severity of the accident can be determined by combining it with the accident condition. it can. Since the discrimination of the accident condition is equivalent to selecting a control table that matches the accident condition, the accident condition is simplified using the accident duration instead of the stability limit value and the stability determination amount in the first embodiment. be able to.

  Therefore, in the first embodiment, the time integral value of the falling portion of the active power during the accident is simplified as the stability limit value and the stability determination amount. In the fourth embodiment, the accident continuation is simplified. Substitute with time. Further, since the active power is not used as the determination amount, the active power measuring unit 5 can be omitted. In this case, the accident detection and the accident removal detection in the accident condition detection means 6 use the transmission line breaker open / close state, protection relay operation information, etc., assuming that no active power is used.

  FIG. 21 is a flowchart showing an example of processing contents of the control generator determination means 7 in the fourth embodiment of the present invention. This is obtained by replacing the stability determination amount calculation in step (S3) with the accident duration measurement with respect to the flow chart of the control generator determining means 7 in the first embodiment shown in FIG. . Of course, the control table shows the correlation between the accident duration and the necessary electric generator, and it is provided for each accident condition. Further, the control table creating means 4 does not need to calculate the stability limit value, and the accident duration and the necessary electric generator are related and stored as a control table. Further, when determining the necessary electric power generator using the control table selected in the step of using the control table, that is, the control table selected in step (S5) of FIG. 21, the accident duration determined in step (S3) is used as a parameter. To do. Thereby, the system stabilization apparatus which simplified compared with 1st Embodiment can be provided.

  Next, a fifth embodiment of the present invention will be described. FIG. 22 is a block diagram of a system stabilizing apparatus according to the fifth embodiment of the present invention. In the fifth embodiment, in contrast to the first embodiment shown in FIG. 1, information useful for the operator among the information obtained by the internal calculation is collected and output to the outside. Means 9 is added. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The analysis information output means 9 collects information useful for the operator out of the information obtained by the internal calculation of the system stabilizing device 1 and outputs it to the outside. In the information output means 9 for analysis, it represents that the control amount is insufficient even if the generator is selected, the function of collecting the internal calculation information of the system stabilizing device 1, the presence / absence of the unstable case, and its accident aspect. Provide a function to output the control amount shortage to the outside. The former function makes it possible to collect analysis data of the system stabilizing device 1. In addition, the latter function allows the operator to make use of the system operation such as restricting the system operation or changing the system configuration with reference to the alarm output. Thereby, since the information obtained by the calculation inside the system stabilizing device 1 can be collected and output, information useful for the operator can be provided as appropriate.

  Next, a sixth embodiment of the present invention will be described. FIG. 23 is a block diagram of a system stabilizing apparatus according to the sixth embodiment of the present invention. In the sixth embodiment, control table information [Tab] is set and inputted from the outside of the apparatus instead of the system model creation means 2 and the analysis condition setting means 3 in contrast to the first embodiment shown in FIG. Interface means 10 is added, and the control table creation means 4 has a stability limit value storage section 4d and a control generator storage section 4f for storing the control table information [Tab] taken in via the interface means 10. Is provided. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In the sixth embodiment, the control table created in the system stabilizing device by the system model creating means 2, the analysis condition setting means 3 and the control table creating 4 in the first embodiment is An equivalent function is provided outside the system stabilizing device 1.

  Depending on the assumed variation of the analysis conditions, it may take time for the calculation processing in the system stabilizing device 1 and performing all calculations in the system stabilizing device may not be feasible. In that case, a configuration is practical in which a computer is installed outside, the control table is created, and the control table information [Tab] is transferred by connecting to the system stabilizing device 1 by a general-purpose communication means. Further, instead of installing a computer externally, the control table information [Tab] is obtained by offline simulation in the human system, as in the case of the conventional offline pre-calculation type system stabilization device, and externally via the interface means 10 A configuration to set is also feasible. Even when the configuration is based on the conventional offline simulation, a highly accurate system stabilization device reflecting actual system conditions and accident conditions can be realized.

  In this way, by providing the transient stability calculation part of the system model creation means 2, the analysis condition setting means 3 and the control table creation means 4 outside, the actual system which is a feature of the present invention is achieved while simplifying the configuration. It is possible to provide a highly accurate system stabilizing device that can reflect the conditions and accident conditions in the calculation.

Next, the stability limit value calculation and control generator determination means in the control table creation means 4 in the first to third embodiments, the fifth embodiment and the sixth embodiment. In the stability determination amount calculation in the 7 stability determination amount calculation unit 7b, the stability limit value and the stability determination amount are calculated by second-order integration with respect to time. The following equation (5) is well known as the equation of motion of the generator.

Here, P _M : mechanical input of the generator G, P _E : electrical output of the generator G, M: inertia constant of the generator, ω _n : rated angular velocity, δ: generator internal voltage phase angle.

It is well known that the generator step-out determination method is performed depending on whether or not the generator internal voltage phase angle δ exceeds 180 degrees. When both sides of the equation (5) are second-order integrated with respect to time, the following equation (6) is obtained.

  Where Δδ is an increase in generator internal voltage phase angle δ.

Equation (6) shows that the increase Δδ of the generator internal voltage phase angle δ can be obtained by second-order integration of the power drop after the accident with respect to time and multiplying by a constant (ω _n / M). ing. In the present invention, Equation (6) is used as a calculation formula for the stability limit value and the stability determination amount. Note that the equation (6) may be simplified so that multiplication by a constant (ω _n / M) is omitted and the calculation is limited to the second-order integration calculation.

  Thereby, it is possible to give physical meaning to the stability limit value and the stability determination amount, that is, the generator internal voltage phase angle. As a result, since the control table becomes intuitively easy to understand, it is possible to provide a system stabilization device that facilitates the validation of the control table, the verification of the stability determination, and the response evaluation.

DESCRIPTION OF SYMBOLS 1 ... System stabilization apparatus, 2 ... System model creation means, 2a ... System state collection part, 2b ... Information storage part, 2c ... System equipment storage part, 2d ... System model creation part, 3 ... Analysis condition setting means, 3a ... System model storage unit, 3b ... operation condition storage unit, 3c ... analysis condition setting unit, 4 ... control table creation means, 4a ... analysis condition storage unit, 4b ... transient stability calculation unit, 4c ... stability determination unit, 4d ... Stability limit value storage unit, 4e ... electric generator selection unit, 4f ... electric generator storage unit, 4g ... stable limit accident duration storage unit, 5 ... active power measurement unit, 6 ... accident condition detection means, 6a ... Accident occurrence detection unit, 6b ... Accident removal detection unit, 6c ... Accident aspect determination unit, 6d ... Main protection operation detection unit, 6e ... Accident point location unit, 7 ... Teleelectric generator determination means, 7a ... Control table determination unit, 7b: Stability judgment amount calculation unit, 7c: Control generator determination , 7d ... accident duration measuring unit, 7e ... pre tidal value holding unit, 8 ... control unit, 9 ... alarm output means, 10 ... interface means

Claims (10)

An analysis system that collects the power grid connection status and power supply and demand status at regular intervals as grid information, and represents the current power flow status based on the collected grid information and pre-stored grid facility data A systematic model creation means for creating a model;
Based on the analysis system model created by the system model creation means, analysis condition setting means for setting a plurality of analysis conditions by changing the accident condition,
For each analysis condition set by the analysis condition setting means, a transient stability calculation is performed while changing a part of the conditions as a parameter, and the generator output active power before the accident and the power generation that changes every moment are combined with the transient stability calculation. The stability judgment amount obtained by time integration of the difference from the machine output active power from the accident occurrence time to the accident removal time is calculated, and the stability of the system phenomenon obtained by the transient stability calculation is judged to be unstable. If it is determined, the stability determination amount is determined as a stability limit value, and the accident removal time, which is one of the conditions of the transient stability calculation, is set as the electric control execution time, and the combination of the electric power generator is changed to change the transient stability. And calculating the optimum electric generator combination that can stabilize the instability phenomenon, determining it as a necessary electric generator, and comparing the stability limit value with the required electric generator. The control table with the control table creation means for storing created for each analysis condition,
Active power measuring means for measuring in real time the generator output active power that changes every moment using the amount of electricity taken from the power system,
Accident condition detecting means for detecting in real time an accident occurrence, accident removal and accident aspect when an accident occurs in the power system,
A control table that matches the accident condition detected by the accident condition detection means is determined from the control tables for each analysis condition created by the control table creation means, and the generator output effective measured by the active power measurement means is determined. The power is input, the stability determination amount is calculated in real time by the same calculation as the control table creation means, and the necessary power corresponding to the stability determination amount calculated in real time with reference to the determined control table. An electric generator determining means for determining an electric generator;
A system stabilization device comprising: control means for disconnecting the electric power generator determined by the electric power generator determination means from the electric power system and stabilizing the electric power system.   The control table creating means creates a control table in which the control timing in the transient stability calculation for obtaining the required control generator is set in consideration of the finish time from the control command output to the circuit breaker opening. The system stabilizing device according to claim 1, wherein   When the generator output active power immediately after the accident is removed is lower than the generator output active power immediately before the accident is removed, the control table creation means determines that the generator output active power value is valid before the accident. The system stabilization apparatus according to claim 1 or 2, wherein the control table is created by continuing to calculate the stability limit value and the stability determination amount until the power is returned.   The control table creating means creates a control table that sequentially controls the generator when a stability determination amount calculated every moment by time integration of active power during an accident reaches a stability limit value. The system stabilizing device according to any one of claims 1 to 3.   The control table creation means has a control table corresponding to main protection operation failure / reserve protection operation, the accident condition detection means has a main protection operation detection unit, and the control generator determination means has main protection operation 5. The control table corresponding to the main protection operation failure / rear protection operation is determined when the main detection operation is detected by the operation detection unit and the accident continues. The system stabilization apparatus of 1 item | term.   The control table creating means has a control table in which a plurality of accident points are changed as analysis conditions, the accident condition detecting means has an accident point locating section, and the electric generator determining means is an accident point locating section. The system stability according to any one of claims 1 to 5, wherein when a fault point is determined in step (b), a control table that is closest to the determined fault point and has a severe stability condition is determined. Device.   The system stabilization apparatus according to claim 1, wherein the control table creation unit performs the calculation of the stability limit value and the stability determination amount by second-order integration with respect to time.   The active power measuring means is removed, the stability limit value and the stability determination amount calculated by the control table creating means and the control generator determining means are replaced with an accident duration, and the control table creating means A control table that associates the accident duration with the necessary electric generator is stored for each analysis condition, and the electric generator determination means determines the necessary electric generator corresponding to the accident duration calculated in real time. The system stabilizing device according to claim 1, wherein the system stabilizing device is determined.   9. The system according to claim 1, further comprising analysis information output means for collecting information useful for an operator out of information obtained by internal computation and outputting the information to the outside. Stabilizer.   Instead of the system model creation means and the analysis condition setting means, an interface means for setting control table information corresponding to the control table from the outside of the apparatus is provided, and the control table creation means is provided via the interface means. 10. A control limit information storage unit for storing a stability limit value in the fetched control table information and a control generator storage unit for storing a control generator are provided. The system stabilization apparatus of any one of these.

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