JP2012170221A - Stability determination device for power system, stabilization system, and method of determining stability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress unnecessary controls for stabilizing a power system such as a restriction of power supply and load, a breaking resistor input, and valve control of a high-speed turbine, when a failure occurs in the power system.SOLUTION: A stability determination device for a power system comprises: a failure condition detecting part for detecting a failed transmission line and kind of failure concerning the failure when a failure occurs in a power system; a determination condition setting part for preliminarily setting determination conditions of the power system stability based on transient stability for each of the failed transmission line, the kind of failure, and the failed point of the failed transmission line; and a determination part for determining the stability of the power system based on the failed transmission line and the kind of failure detected by the failure condition detecting part, on the failed point oriented by a failed point orientation part, and on the determination conditions preliminarily set by the determination condition setting part, when the failure occurs in the power system.

Description

  The present invention relates to a power system stability determination device, a stabilization system, and a stability determination method.

  When a fault such as a short circuit accident or a ground fault occurs in the power system, the balance between the mechanical input and electrical output of the generator connected to the power system is lost, and the generator cannot maintain synchronous operation. May step out. Therefore, the transient stability at the time of failure occurrence is calculated in advance, and after the failure occurrence, the power source limitation and load limitation, braking resistance (SDR: System Damping Resistor, Stabilizing Damping Resistor) required for system stabilization based on the transient stability calculation ) System stabilization control such as charging, high-speed turbine valve control (EVA: Early Valve Actuation) is performed.

  Further, for example, in Patent Document 1, the stability of the electric power system is quickly increased by setting in advance for each accident information a settling value as a stability determination condition based on the result of performing the transient stability calculation in advance. A pre-computation type transient stabilization device that can be obtained is disclosed. Furthermore, in the transient stabilization device of Patent Document 1, the pre-calculation of the determination condition is performed off-line, whereas in the power system stabilization device disclosed in Patent Document 2, for example, it is online every predetermined cycle. The transient stability calculation is performed based on the system information collected in step 1, and the system stability determination condition is pre-calculated.

  Thus, the stability of the power system can be quickly determined by presetting the system stability determination condition offline or online.

JP 2007-159199 A JP-A-8-182199 JP-A-9-5384

  By the way, when a failure occurs in the power system, failure point location is performed to calculate the position of the failure point for the purpose of early investigation of the cause of the failure and early recovery of the power system. For example, Patent Document 3 discloses a failure point locating device that can reduce facility costs and installation space using a conventional PCM relay.

  However, in the transient stabilization device of Patent Document 1 and the power system stabilization device of Patent Document 2, the stability determination condition at the time of failure in the transmission line is usually the most severe condition in order to prevent step-out as much as possible, that is, It is set assuming a failure at the closest end of the transmission line. Therefore, depending on the actual position of the failure point, unnecessary system stabilization control may be performed even when system stabilization control such as power limitation can be avoided.

  The main present invention for solving the above-described problem is that when a failure occurs in an electric power system, a failure condition detection unit that detects a failure transmission line and a failure type of the failure, the failure transmission line, the failure type, and the A determination condition setting unit that presets a determination condition for the stability of the power system based on transient stability for each failure point in a faulty transmission line, and the failure condition detection unit when the failure occurs in the power system Based on the failure transmission line and the failure type detected by the failure point, the failure point determined by the failure point locating unit, and the determination condition preset by the determination condition setting unit. A determination unit for determining the degree of stability.

  Other features of the present invention will become apparent from the accompanying drawings and the description of this specification.

  ADVANTAGE OF THE INVENTION According to this invention, system | strain stabilization control, such as an unnecessary power source limitation and load limitation at the time of a failure in an electric power system, braking resistance input, and high-speed turbine valve control, can be suppressed. In the following, a case where power supply restriction is performed will be described as an example of system stabilization control. However, even when other system stabilization control is performed, only the contents of the control are different, and similarly unnecessary system stabilization control is performed. Can be suppressed.

It is a block diagram which shows the structure of the stability determination apparatus of the electric power grid | system in one Embodiment of this invention. It is a block diagram which shows an example of a structure of the electric power system to which the stability determination apparatus and stability determination method of the electric power system in one Embodiment of this invention are applied. It is a block diagram which shows an example of a specific structure of the terminal device 2a. It is a block diagram which shows an example of a specific structure of the terminal device 2b. 6 is a flowchart illustrating an operation of a determination condition setting unit 102. It is a figure which shows an example of the failure classification assumed. It is a figure which shows an example of the unstable area UA (Gs, Lf, Tf) calculated by the determination condition setting part.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

=== Example of power system configuration ===
Hereinafter, with reference to FIG. 2 thru | or FIG. 4, the structure of the electric power system with which the stability determination apparatus and stability determination method of the electric power system in one Embodiment of this invention are applied is demonstrated. In the power system, each circuit breaker may be connected to a switch such as a disconnect switch in series, and the circuit breaker information may include information on the switch.

  In the power system shown in FIG. 2, the controlled power plant includes three generators 10, 20, and 30. Moreover, the transformers 11, 21, and 31 are installed at the output ends of the generators 10, 20, and 30, respectively. From the transformers 11, 21, and 31, (generator) voltage information V 1, V2 and V3 are output. Further, current transformers 12, 22, and 32 are installed at the output ends of the generators 10, 20, and 30, respectively, and (generator) current information is respectively received from the current transformers 12, 22, and 32. I1, I2, and I3 are output. And the generators 10, 20, and 30 are connected to the bus-line 40 via the circuit breakers 13, 23, and 33, respectively. The circuit breakers 13, 23, and 33 are controlled by control signals S1, S2, and S3, respectively, and output circuit breaker information B1, B2, and B3 (for generators) indicating respective on / off states.

  The duplexed bus 40 is provided with instrument transformers 41, 42, and the outputs of the instrument transformers 41, 42 are output as (bus) voltage information V 4 via the automatic switching device 43. ing. Further, a BP (Busbar Protection) relay 44 is installed on the bus 40, and (bus) protection relay operation information R <b> 4 is output from the BP relay 44.

  Power transmission lines 50 and 60 are connected to the bus 40 on the power transmission end side through circuit breakers 53 and 63, respectively. In addition, LP (Line Protection) relays 51 and 61 are respectively installed at the power transmission ends of the power transmission lines 50 and 60. From the LP relays 51 and 61, (power transmission line) protection relay operation information R5, R6 is output. Furthermore, current transformers 52 and 62 are installed at the power transmission ends of the power transmission lines 50 and 60, respectively, and (transmission line) current information I5 and I6 are output from the current transformers 52 and 62, respectively. ing. The circuit breakers 53 and 63 output circuit breaker information B5 and B6 (for power transmission lines) indicating the respective on / off states.

  The power transmission lines 50 and 60 are connected to the power receiving end side bus 90 via circuit breakers 73 and 83, respectively. In addition, LP relays 71 and 81 are installed at the power receiving ends of the power transmission lines 50 and 60, and (power transmission line) protection relay operation information R7 and R8 are output from the LP relays 71 and 81, respectively. Further, current transformers 72 and 82 are installed at the power receiving ends of the power transmission lines 50 and 60, respectively, and (transmission line) current information I7 and I8 are output from the current transformers 72 and 82, respectively. ing. The circuit breakers 73 and 83 output circuit breaker information B7 and B8 (for power transmission lines) indicating respective on / off states.

  The duplexed bus 90 is provided with instrument transformers 91 and 92, and the outputs of the instrument transformers 91 and 92 are output as (bus) voltage information V9 via the automatic switching device 93. ing. Further, a BP relay 94 is installed on the bus 90, and (bus) protection relay operation information R9 is output from the BP relay 94. The bus 90 is connected to other power plants, substations, and the like via circuit breakers 95 and 96, and collects system information and failure information necessary for system stabilization control described later.

  The terminal device 2a is installed in the vicinity of the bus 40 on the power transmission end side, and the terminal device 2b is installed in the vicinity of the bus bar 90 on the power receiving end side. In addition, terminal devices 2c to 2f are also installed in other power plants and substations that are targets of collection of system information and failure information necessary for the system stabilization control. Note that the terminal device 2b and other terminal devices such as the other power plants and substations receive information for performing system stabilization control as necessary, and normally send control signals corresponding to the information. Has a function to output.

  As illustrated in FIG. 3, the terminal device 2 a includes a system information collection unit 201, a failure information collection unit 202, a power supply restriction unit 203, FS (Fail-Safe) relays 204 and 205, and a transmission unit 206. It is configured. In the present embodiment, the terminal device 2a includes a power limiting unit, functions as a power limiting device (system stabilization control device), and configures a power system stabilization system together with the stability determination device 1 described below.

  The system information collection unit 201 includes voltage information V1, V2, V3, V4, current information I1, I2, I3, I5, I6, circuit breaker information B1, B2, B3, B5, B6, and protection relay operation information R4, R5 and R6 are input. Further, the system information collection unit 201 outputs system information SIa indicating the connection state of the power system, the power supply / demand state, and the like based on the input information. The system information SIa is transmitted via the transmission unit 206. Has been sent. In addition, the connection state of the power system, the supply and demand state of power, and the like are based on voltage information V1, V2, V3, V4, current information I1, I2, I3, I5, I6, breaker information B1, B2, B3, B5, B6. Since it can be understood, the input of the protection relay operation information R4, R5, R6 may be omitted.

  The failure information collection unit 202 receives protection relay operation information R4, R5, and R6. Further, the failure information collection unit 202 outputs failure information FIa indicating that a failure has occurred in the bus 40 or the power transmission lines 50 and 60 based on the input information. The failure information FIa is transmitted from the transmission unit 206. Has been sent through. Note that the terminal device 2a outputs an enable signal EN1 that permits the output of the failure information FIa based on the voltage information V4 and the current information I5 and I6 in order to prevent the failure information FIa from being erroneously transmitted. An FS relay 204 is provided.

  The power source restriction unit 203 is input with the generator information GI described later (target power source restriction) via the transmission unit 206. In addition, the power supply restriction unit 203 outputs control signals S1, S2, and S3 for performing power restriction as necessary based on the generator information GI. Then, in accordance with the control signals S1, S2, and S3, power supply restriction such as shutting off a power supply restriction target generator is performed. The terminal device 2a outputs the control signals S1, S2, and S3 based on the voltage information V1, V2, and V3 and the current information I1, I2, and I3 in order to prevent the power supply from being erroneously restricted. An FS relay 205 that outputs an enable signal EN2 to be permitted is provided.

  As illustrated in FIG. 4, the terminal device 2 b includes a system information collection unit 201, a failure information collection unit 202, an FS relay 204, and a transmission unit 206.

  Voltage information V9, current information I7, I8, breaker information B7, B8, and protection relay operation information R7, R8, R9 are input to the system information collection unit 201. Further, the system information collection unit 201 outputs system information SIb indicating the connection state of the power system, the power supply / demand state, and the like based on the input information. The system information SIb is transmitted via the transmission unit 206. Has been sent. In addition, since the connection state of an electric power system, the supply-and-demand state of electric power, etc. can be grasped | ascertained from voltage information V9, current information I7, I8, and circuit breaker information B7, B8, input of protection relay operation information R7, R8, R9 May be omitted.

  The failure information collection unit 202 receives protection relay operation information R7, R8, and R9. Also, the failure information collection unit 202 outputs failure information FIb indicating that a failure has occurred in the bus 90 and the power transmission lines 50 and 60 based on the input information. The failure information FIb is transmitted from the transmission unit 206. Has been sent through. The terminal device 2b outputs an enable signal EN1 that permits the output of the failure information FIb based on the voltage information V9 and the current information I7 and I8 in order to prevent the failure information FIb from being transmitted accidentally. An FS relay 204 is provided.

  The terminal devices 2c to 2f have the same configuration as the terminal device 2a or 2b, and at least system information SIc to SIf and failure information FIc to FIf are transmitted from the terminal devices 2c to 2f, respectively.

=== Configuration of Stability Determination Device ===
Hereinafter, with reference to FIG. 1, the structure of the stability determination apparatus of the electric power system in one Embodiment of this invention is demonstrated.

  The stability determination device 1 shown in FIG. 1 includes a transmission unit 101, a determination condition setting unit 102, a failure condition detection unit 103, a failure point location unit 104, and a determination unit 105.

  System information SIa to SIf is input to the determination condition setting unit 102 via the transmission unit 101, and unstable region information UA (Gs, Lf, Tf) is output from the determination condition setting unit 102. Further, failure information FIa to FIf is input to the failure condition detection unit 103 via the transmission unit 101, and the failure transmission line information Lf and failure type information Tf are output from the failure condition detection unit 103. Further, the system information SIa to SIf and the failure information FIa to FIf are input to the failure point location unit 104, and the failure point location result information Pf is output from the failure point location unit 104. Unstable area information UA (Gs, Lf, Tf), fault power transmission line information Lf, fault type information Tf, and fault location information Pf are input to the determination unit 105. Generator information GI indicating a generator that needs to be power-restricted in order to stabilize the system is output, and the generator information GI is transmitted via the transmission unit 101.

=== Operation of Stability Determination Device ===
The operation of the power system stability determination device according to this embodiment will be described below with reference to FIGS. 5 to 7 as appropriate.

  The determination condition setting unit 102 acquires system information SIa to SIf for each predetermined period, and calculates unstable region information UA (Gs, Lf, Tf) based on transient stability. The unstable area information UA (Gs, Lf, Tf) is used by the determination unit 105 as a predetermined stability determination condition.

Here, FIG. 5 shows a more specific operation of the determination condition setting unit 102.
When the determination condition setting unit 102 starts the determination condition setting process (S101), the determination condition setting unit 102 first acquires system information SIa to SIf (S102).

  Next, the determination condition setting unit 102 calculates the transient stability under a predetermined analysis condition (Gs, Lf, Tf) for each failure point (Pf) in the failed transmission line based on the system information SIa to SIf ( S103). Here, the predetermined analysis condition (Gs, Lf, Tf) is a case where the power limit state (Gs), the fault power transmission line (Lf), and the fault type (Tf) are predetermined, for example, power limit is performed. The transient stability when a three-wire ground fault (Tf) occurs in the transmission line 50 (Lf) in the absence state (Gs) is calculated for each of a plurality of failure points (Pf) on the transmission line 50. FIG. 6 shows an example of assumed failure types, and the failure types for calculating the transient stability are selected from these failure types as necessary.

  In the process of calculating the transient stability for each failure point (Pf), by obtaining the limit failure point where stability / instability is switched, when the calculation result ahead of the limit failure point is clear, Subsequent calculations can be omitted.

  Next, the determination condition setting unit 102, based on the calculation result of the transient stability for each failure point (Pf), the failure point (Pf) where the power system becomes unstable under a predetermined analysis condition (Gs, Lf, Tf). ) Is calculated as unstable area information UA (Gs, Lf, Tf) (S104).

  Further, the determination condition setting unit 102 changes the analysis condition (Gs, Lf, Tf) to change the unstable region for each power supply restriction state (Gs), fault power transmission line (Lf), and fault type (Tf). Information UA (Gs, Lf, Tf) is calculated (S103 to S104).

  Increasing the power supply limit makes the power system more stable and results in a calculation that reduces the unstable area.Therefore, the unstable area obtained when power supply is not restricted or when the power supply restriction is low When the calculation result in a state where the power supply restriction amount is larger is clear from the limit failure point, the subsequent calculation can be omitted.

  Then, the determination condition setting unit 102 acquires the system information SIa to SIf at predetermined intervals (S102 to S104).

  In the present embodiment, as in the power system stabilization device of Patent Document 2, the system information SIa to SIf is acquired online every predetermined period, and the unstable area information UA (used as a stability determination condition) Gs, Lf, Tf) are pre-computed. However, similar to the transient stabilization device disclosed in Patent Document 1, the determination condition pre-calculation may be performed offline. As stability determination conditions, stable area information or the limit failure point (Pf) may be used instead of unstable area information UA (Gs, Lf, Tf). Further, the calculation result of the transient stability for each failure point (Pf) may be used as it is as the determination condition.

  When a failure occurs in the power system and the failure information FIa to FIf is input, the failure condition detection unit 103 detects the failure transmission line and the failure type of the failure, and the failure transmission line information Lf and the failure type information respectively. Output as Tf.

  When a failure occurs in the power system and the failure information FIa to FIf is input, the failure point locating unit 104 locates the failure point in the failed transmission line based on the currently failed system information SIa to SIf. Output as point location result information Pf. For example, by using a PCM relay as the LP relays 51, 61, 71, 81, the failure point can be determined in the same manner as the failure point locating device of Patent Document 3. Further, as a fault location method, other methods such as a zero-phase current shunt ratio method, an impedance method, a pulse radar method, and a surge reception method may be used. Further, the fault point location is performed in the terminal device 2a, and the fault point location result information Pf is acquired together with the fault information FIa to FIf via the transmission unit 101, and the stability determination device 1 and other terminal devices are independent. It is good also as a structure which acquires failure point location result information Pf from this failure point location apparatus.

  The determination unit 105 includes unstable area information UA (Gs, Lf, Tf) preset as stability determination conditions, failure transmission line information Lf input when a failure occurs, failure type information Tf, and failure location. The stability of the power system is determined based on the result information Pf. Then, in accordance with the determination result, the determination unit 105 selects a power supply restriction target generator and outputs it as generator information GI in order to prevent step-out in the power system.

  Here, an example of the unstable area UA (Gs, Lf, Tf) calculated by the determination condition setting unit 102 is shown in FIG. In FIG. 7, a three-wire ground fault (Tf) occurred in the transmission line 50 or 60 (Lf) in a state where the power source is not restricted and in a state where the power source is restricted for the generators 10, 20 and 30 (Gs). The unstable region UA (Gs, Lf, Tf) in the case is shown.

  As shown in FIG. 7, when the power supply is not limited, if a three-wire ground fault occurs in the area A1 to A7, the generator 10, 20, 30 will step out, etc. Becomes unstable. Further, when the power supply of the generator 10 is limited, if a three-wire ground fault occurs in the region A1 to A5, the power system becomes unstable due to the generators 20 and 30 stepping out. Furthermore, when the power source of the generator 20 is limited, if a three-wire ground fault occurs in the region A1 to A3, the power system becomes unstable due to the generators 10 and 30 stepping out. When the power source of the generator 30 is limited, the power system does not become unstable even if a three-wire ground fault occurs in any region. In the present embodiment, in consideration of the error in the fault location, etc., a part of A8 when the power supply is not restricted, a part of A6 when the power supply of the generator 10 is restricted, the generator When power supply is limited to 20, a part of A4 is added to the unstable area UA (Gs, Lf, Tf), and the unstable area UA (Gs, Lf, Tf) is added to the safe side (the direction in which the unstable area increases). However, the failure point location result information Pf may be corrected to the safe side.

  In the state of FIG. 7, conventionally, the power source of the generator 30 was limited regardless of where the 3-wire ground fault occurred in the transmission line 50 or 60 (Lf). When the error occurs at the unit, A9, or A10, it is not necessary to perform power supply restriction, and unnecessary power supply restriction can be suppressed. When a 3-wire ground fault occurs in a part of A6, A7, or a part of A8, the determination unit 105 selects the generator 10 as a power restriction target, and the power restriction part of the terminal device 2a. Restricts the power supply of the generator 10 based on the generator information GI. Furthermore, when the 3-wire ground fault accident occurs in a part of A4, A5, or a part of A6, the determination unit 105 selects the generator 20 as a power restriction target, and the power restriction part of the terminal device 2a. Restricts the power supply of the generator 20 based on the generator information GI. When the 3-wire ground fault occurs in any one of A1 to A4, the determination unit 105 selects the generator 30 as a power supply restriction target, and the power supply restriction unit of the terminal device 2a is the generator. Based on the information GI, the power supply of the generator 30 is limited.

  In this way, the stability determination device 1 determines the stability of the power system using the unstable region information UA (Gs, Lf, Tf), and aims to minimize the power limit amount, for example. The machine is selected. As system stabilization control, other methods such as load limitation, input of limiting resistance, and high-speed turbine valve control may be used instead of power source limitation or as additional control.

  As described above, in the power system stability determination device 1, the transient stability is calculated for each fault transmission line (Lf), fault type (Tf), and fault point (Pf), and the unstable area information UA ( Gs, Lf, Tf) are set in advance as stability determination conditions, and when a fault occurs in the power system, the fault transmission line and the fault type are detected, and the fault point in the fault transmission line is determined. By determining the stability of the power system based on the unstable area information UA (Gs, Lf, Tf), it is possible to suppress system stabilization control such as unnecessary power supply limitation when a failure occurs in the power system. In addition, by suppressing unnecessary power supply restrictions, system frequency reduction due to power supply restrictions can be suppressed, and load interruption to maintain the system frequency can be suppressed. It is possible to save the fuel required for the project and to reduce carbon dioxide emissions.

  In addition, the system information SIa to SIf is acquired online every predetermined period, and the current state of the power system is obtained by performing pre-calculation of the unstable area information UA (Gs, Lf, Tf) used as the stability determination condition. It is possible to select an optimal power source restriction target generator according to the operating state.

  Moreover, the system stabilization control which prevents the out-of-step in the electric power system is performed by selecting a power supply restriction target generator according to the stability determination result based on the unstable area information UA (Gs, Lf, Tf). be able to.

  In addition, transient stability is calculated for each failure transmission line (Lf), failure type (Tf), and failure point (Pf), and stability determination conditions are set in advance, and a failure has occurred in the power system. When a fault occurs in the power system, the fault transmission line and the fault type are detected, the fault point in the fault power transmission line is determined, and the stability of the power system is determined based on preset determination conditions. System stabilization control such as unnecessary power supply restrictions can be suppressed.

  In addition, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Stability determination apparatus 2a-2f Terminal device 10, 20, 30 Generator 11, 21, 31 Instrument transformer 12, 22, 32 Instrument current transformer 13, 23, 33 Circuit breaker 40, 90 Bus 41, 42 , 91, 92 Instrument transformer 43, 44 Automatic switching device 44, 94 BP (bus protection) relay 95, 96 Circuit breaker 50, 60 Transmission line 51, 61, 71, 81 LP (transmission line protection) relay 52, 62 , 72, 82 Current transformer 53, 63, 73, 83 Circuit breaker 101 Transmission unit 102 Judgment condition setting unit 103 Fault condition detection unit 104 Fault point location unit 105 Judgment unit 201 System information collection unit 202 Fault information collection unit 203 Power limiter 204, 205 FS (fail safe) relay 206 Transmitter

Claims (7)

When a failure occurs in the power system, a failure condition detection unit that detects a failure transmission line and a failure type of the failure,
A determination condition setting unit that presets a determination condition for the stability of the power system based on transient stability for each failure point in the failed transmission line, the failure type, and the failed transmission line;
When the fault occurs in the power system, the fault transmission line and the fault type detected by the fault condition detection unit, the fault point determined by the fault point determination unit, and the determination condition setting unit A determination unit that determines the stability of the power system based on the determination condition set in advance by
A power system stability determination device characterized by comprising:   The power system stability determination device according to claim 1, further comprising a failure point locating unit that locates the failure point in the failed transmission line when the failure occurs in the power system.   The determination condition setting unit obtains, as system information, a connection state of the power system and a power supply / demand state in the power system for each predetermined period, and calculates the transient stability based on the system information. The power system stability determination device according to claim 1 or 2, wherein the determination condition is set in advance. A power system stability determination device according to any one of claims 1 to 3,
In accordance with the determination result of the determination unit, a system stabilization control device that performs system stabilization control to prevent step-out in the power system,
A power system stabilization system comprising:   5. The system stabilization control device according to claim 4, wherein the system stabilization control apparatus performs system stabilization control that is power source limitation, load limitation, braking resistance input, high-speed turbine valve control, or a combination thereof. Stabilization system.   The power system stabilization system according to claim 5, wherein the system stabilization control device performs power supply restriction by selecting a power supply restriction target generator from power generators of the power system. For each fault point in the fault power transmission line, fault type, and fault power transmission line when a fault occurs in the power system, the determination condition for the stability of the power system based on transient stability is set in advance,
When the failure occurs in the power system, the failure transmission line and the failure type are detected and the failure point is determined, the failure transmission line, the failure type, and the failure point, and the determination condition And determining the stability of the power system based on the power system.

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