JPH08223800A - Fault detector for link system - Google Patents

Abstract

PURPOSE: To prevent a system fault from being overlooked and to raise the accuracy of fault judgment by calculating the gradient of the change of element information, and detecting a power disconnection fault and a load disconnection fault on the basis of a total generated power, a total demand power, and the gradient of the change of frequency out of the element information, when a rapid change of the element information is detected. CONSTITUTION: A cyclic digital telemeter(CDT) input processing part 50 receives element information periodically as input, and stores the present values and last-time values inputted. A change calculating part 60 compares the present values with the last-time ones of frequency and link line power flow out of the element information inputted, and calculates the gradients of their changes when their rapid changes are detected. A fault detecting part 70 detects a power disconnection fault and a load disconnection fault on the basis of a total generated power, a total demand power, and the gradient of the change of frequency calculated by the change calculating part 60, out of element information. Consequently, it becomes possible to prevent a system fault from being overlooked, and to raise the accuracy of fault judgment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an accident in a power system of each electric power company in an interconnection system in which electric power systems of a plurality of electric power companies are interconnected and electric power is exchanged between the electric power companies. The present invention relates to an interconnected system accident detection device.

[0002]

2. Description of the Related Art In Japan, there is a power supply system of nine power companies, and each power company is responsible for power supply in its own jurisdiction. Generally, each power company operates its own power grid. There is. On the other hand, in order to effectively utilize the equipment and resources between each electric power company, the electric power system of each electric power company is connected by an interconnection line to exchange electric power. For example, in the event of a major accident such as a grid drop of a large-capacity generator or a grid drop of a large-capacity load, electric power is exchanged through an interconnection line for the purpose of emergency power interchange between electric power companies.

As an engine for smoothly and appropriately promoting power interchange between electric power companies during normal times and at the time of an accident, a central power supply communication command center (hereinafter, referred to as "intermediate supply station") is installed. This middle-paid station is networked with the central power supply command center of each electric power company (hereinafter referred to as the middle-paid office).
Command operations such as how much power is to be exchanged from the A electric power company to the B electric power company based on the request from each middle salary,
Plan daily power interchange plans.

In addition, when a large-capacity power plant dropout accident (hereinafter referred to as a power supply dropout accident) or a large-capacity load dropout accident (hereinafter referred to as a load dropout accident) occurs in the interconnection system, an accident similarly occurs. Based on the request from the electric power company, the electric power company with a surplus power will urgently support and stabilize the power supply on a nationwide scale.

[0005] In order to carry out such a task, the middle-paid ream, from the middle-paid to the system frequency in each power company,
The power of the interconnection line, the total power generation of each power company, the total power demand of each power company, etc. are constantly transmitted. These pieces of information are displayed on the monitoring panel and recorded on a paper chart.

[0006] FIG. 14 is an explanatory diagram of a relationship between medium-paid and medium-paid relay in each electric power company connected by an interconnection line. Each electric power company 1 is interconnected by an interconnection line 2. Each power company 1
Each of them is provided with a medium feed 3, and information is transmitted to the medium feed station 6 via a CDT device 4 (cyclic digital telemeter device) which is a kind of information transmission device and a transmission line 5.

Interchange power (hereinafter referred to as tidal current) for the purpose of effective utilization of equipment and resources of each electric power company 1 flows through the interconnection line 2, and information about these tidal currents and grid frequency of each electric power company. Is sent from the intermediate feed 3 to the intermediate feed station 6 through the CDT device 4 and the transmission line 5.

[0008] FIG. 15 shows the substation 7 in each electric power company.
It shows the transmission of information from the middle-pay to the middle-paid station 6 and the transmission of information from the middle-paid station to the middle-paid station 6. From the power substation 7, the generated power and demand power at that time are constantly transmitted to the intermediate supply 3. Further, at the substation for detecting frequency and interconnection power flow, the frequency and interconnection power flow are also transmitted to the intermediate supply 3. Although a CDT device is used as a device for transmitting such information, a small amount of highly urgent information such as frequency and interconnection current is transmitted by a dedicated line. Upon receiving these information, the intermediate salary periodically calculates the operating data such as total power demand and total power generation for the entire electric power company based on the information from each substation and uses it for its own grid operation. are doing.

In the intermediate pay 3, the information such as the frequency and the interconnection line power flow that does not require the processing calculation is transferred to the intermediate pay station 6 each time it is received, and the total generated power and the total demand power are calculated every time the intermediate pay is performed. It is transmitted to the station 6 via the CDT device 4. Hereinafter, these frequencies, the interconnection line power flow, the total power generation amount area, and the total demand power, which are the information transmitted to the intermediate feed station 6, are collectively referred to as element information.

The CDT device 4 of the intermediate feeding station 6 transmits these received element information to the monitoring board control device 8, where a digital signal is converted into an analog signal, which is displayed on the meter 9 and displayed on the paper chart 10. To record. The watchman of the middle-pay station 6 monitors these element information sent from each middle-pay station 3 on the instrument 9 on the monitor panel control device 8 and on the paper chart 10, and determines the occurrence of an accident from these movements. When it is determined that an accident has occurred, the outline of the accident is estimated even if the power company does not request emergency support. In other words, it estimates what kind of accident occurred and at what scale, and starts preparing for power interchange adjustment. This prevents the emergency support from being too late. Accidents captured here include power loss and load loss.

The reason why the middle-ranked ream 6 independently estimates an accident before receiving an emergency support request from the electric power company is as follows. (A) When an accident occurs, the power company's mid-payment 3 is trying to recover itself, and is being overwhelmed by the accident response.
There is a possibility that a support request may be sent to the Churenren 6. (B) The greater the accident, the greater the degree of emergency for the support from other electric power companies. If support can be sent, the impact of the accident may spread to other electric power companies. (C) It is a relatively small accident, and when it can be handled by the company, it does not contact the CPA 6, but the CPA 6 wants to know the situation of the accident.

The reason for the occurrence of an accident is not judged only by the change of a single data such as frequency or interconnection power flow, but is comprehensively judged from the change of the whole element information for the following reason. That is, the element information, especially the frequency and the interconnection line power flow, are constantly changing according to the balance of supply and reception at that time. If the system scale is large, small accidents have little effect on these, and although the gradient of change is steep, the amount of change is small and it is difficult to distinguish it from normal changes. Therefore, it is difficult to judge this as an accident by itself.

On the other hand, the total generated power usually changes gradually when the generator is stopped during operation and becomes steep when the accident is lost. In practice, the middle salary 3 is generally subjected to a smoothing process such as a moving average according to the data of what time, and the middle salary station 6 receives the smoothed value. Therefore, it is difficult to judge an accident based on this data alone.

For these reasons, the middle-end payer 6 judges the presence / absence of an accident by observing the change in the entire element information. For example, if there is a decrease in the frequency or an increase in the inflow of the interconnection line power flow and a decrease in the total generated power, it is determined that the power supply has dropped. In addition, if there is an increase in frequency or an increase in tidal current outflow on the interconnection line and the total power demand decreases, it is determined that a load drop accident has occurred.

[0015]

However, when an accident occurs at an electric power company somewhere in the Churenren, it is necessary to immediately grasp the accident and start preparations for emergency power interchange. There was a problem of accuracy of accident judgment and a problem of accident judgment timing.

For example, in the interconnection system as shown in FIG. 16 (a), while the electric power company 1B and the electric power company 1C are transmitting and receiving 50 MW to and from the electric power company 1B, respectively, the electric power company 1B. If a 100 MW generator is lost, the frequency, interconnection line power flow, and total generated power will change, as shown in FIG. 16 (b), so the 100 MW power loss accident of power company 1B will depend on these changes. It can be estimated at first. Here, the upward arrow in FIG. 16 (b) means upward increase and the downward arrow means downward decrease.

However, the actual estimation has the following problems. (A) Information from each payroll is displayed on a monitoring panel and recorded on a paper chart, and although the shift staff constantly monitors these, it does not mean that they are always focusing on specific equipment. However, it may be overlooked with a temporary touch of the instrument. (B) I have also recorded on the paper chart, but this is 3c
Since it is expressed by a time schedule of about m / 1 hour, it is difficult to determine the steepness even if it can be determined that there has been a change. In other words, it is difficult to determine the gradient, which is the amount of change per unit time, and it is difficult to distinguish whether it is a change due to an accident or a change during normal times, for example, whether the pumped-storage generator is started or stopped. Therefore, there is a risk of misunderstanding whether it is an accident or not. (C) Each element information is recorded on a separate paper chart,
Moreover, since there is a deviation in the timing of information transmission, it is difficult to compare information at the same time. In other words, the frequency and the power flow on the interconnection line are transmitted promptly, but the total power generation and the total demand power are transmitted after a few minutes, so it is difficult to determine the simultaneity of the times of the respective element information. For this reason, it is impossible to make a judgment or it takes a long time to make a judgment, so that the timing of accident judgment is delayed.

FIG. 17 is a transmission time chart to the intermediate feed station 6 when the large capacity generator is dropped. Changes in frequency and power flow in the interconnection line can be captured by the intermediate feed station 6 within about several seconds, but changes in total power generation cannot be captured until after several tens of seconds to several minutes. That is, the interconnection line flow is the most important information, and since no processing calculation is required in the intermediate feed 3, the detected value is transferred to the intermediate feed as it is. Therefore, the delay time is within several seconds when viewed from the middle-pay station 6.

On the other hand, regarding the total power generation and the total power demand, the power generation and the power demand from each substation are collected for a fixed period, for example, from several tens of seconds to several minutes, and the total is calculated. Will be significant data for the first time. In addition, the urgency of information is low compared to frequency and interconnection current. Therefore, the transmission to the medium feed station is at intervals of several tens of seconds to several minutes. As described above, since there is a difficulty in determining element information, it is easy to take time to estimate the occurrence of an accident and misidentify it.

It is an object of the present invention to provide an interconnected system accident detection device capable of preventing a system accident from being overlooked, improving the accuracy of accident determination, and detecting an accident at an earlier timing.

[0021]

An interconnected system accident detection apparatus according to the present invention includes a CDT input processing unit for periodically inputting element information and storing the input current value and previous input value.
Of the input element information, the current value and the previous value for the frequency and interconnection power flow are compared, and when a sudden change is detected, the change amount calculation unit that calculates the change gradient and the total generated power and total An accident detection unit that detects a power supply drop accident and a load drop accident based on the power demand and the frequency change gradient.

Then, the accident detection unit disconnects the power source when the change gradient of the decrease in frequency is steeper than the preset value and the decrease in the total power generation of the element information is larger than the predetermined value. It is determined that an accident has occurred, and when the change gradient of the increase in frequency is steeper than the preset value and the decrease in the total power demand in the element information is steep, it is determined that a load drop accident has occurred.

If necessary, the accident detection section is provided with a simultaneous power supply load drop detection function for detecting the occurrence of both a power drop accident and a load drop accident in the power system of the same power company. The power load simultaneous dropout detection function has caused both a power drop accident and a load drop accident when the amount of decrease in total power generation is larger than a predetermined set value and the amount of decrease in total power demand is larger than a predetermined set value. I am trying to judge.

Further, the accident detection result of the accident detection unit is transmitted to the central power supply command center of each electric power company. Further, the predetermined set value of the frequency change gradient in the accident detection unit is set based on the total power demand of the entire interconnection system.

[0025]

In the present invention, the interconnected system accident detection device is C
The DT input processing unit periodically inputs the element information and stores the current value and the previous value, and the change amount calculation unit calculates the current value and the previous value for the frequency and the interconnection line power flow in the input element information. When the sudden change is detected, the change gradient is calculated. Then, the accident detection unit detects a power drop accident and a load drop accident based on the total generated power, the total demand power, and the frequency change gradient in the element information. In this case, the accident detection unit determines that the power drop accident occurs when the change gradient of the frequency decrease is steeper than the predetermined set value and the decrease in the total power generation of the element information is larger than the predetermined set value. If the change gradient of the frequency increase is steeper than the preset value and the decrease of the total demand power in the element information is steep, it is determined that the load drop accident.

In addition, if necessary, the power load simultaneous loss detection function detects in the accident detection unit that both a power loss accident and a load loss accident have occurred in the power system of the same power company. This power load simultaneous dropout detection function causes both a power drop accident and a load drop accident when the total power generation decrease amount is larger than a predetermined set value and the total power demand decrease amount is larger than a predetermined set value. It is judged that it did. And
The accident detection result in the accident detection unit is transmitted to the central power supply command center of each electric power company. This allows each electric power company to understand the situation of the accident. Further, since the preset value of the frequency change gradient in the accident detection unit is determined based on the total power demand of the entire interconnection system,
Accidents can be determined according to changes in total power demand.

[0027]

Embodiments of the present invention will be described below. FIG. 1 is an overall configuration diagram in which the accident detection device 11 of the present invention is applied to an interconnection system. The same elements as those of the conventional one shown in FIG. 15 are designated by the same reference numerals, and the description thereof will be omitted. In the present invention, an accident detector 11 and a display device 1 are provided at the central power supply communication command center 6.
2 and are provided.

The accident detection device 11 contains a program, which is constructed as shown in FIG.
That is, the CDT input processing unit 50, the change amount calculation unit 60,
It is composed of an accident detection unit 70 and an output processing unit 80, and has a table for storing information necessary for the operation of these units and the operation result.

The CDT input processing unit 50 inputs the element data from the CDT device 4 periodically, for example, from 1 second to several seconds, and stores this as a table in a main memory or a desk memory in a predetermined format as shown in FIG. It is stored, and is functionally composed of two functions, a rearrangement process 51 and an input process 52. That is, in the CDT input processing unit 50, first, the current value at the time of the previous processing is moved to the previous value area of FIG. 3A by the rearrangement processing 51, and then the current element information from the CDT device 4 is input at the input processing 52. Is input and is stored in the current value area of FIG.

The change amount calculation unit 60 calculates a sudden change point, that is, a steep change point, a change amount and a gradient (change amount / time) for each element information, which is input and stored in the CDT input processing unit 50. This calculation is performed from the difference between the current value and the previous value.

The change amount calculation unit 60 detects the change point start point 6
1 and a change point start point detection determination process 62 and a maximum change amount calculation process 63. This change point start point detection processing 61 detects a sudden change from the difference between the current value and the previous value, and when it is determined that a sudden change has occurred, it stores information next in the change amount table shown in FIG.

The "change time" is the previous value input time, the "before change" is the previous value, the "change amount" is the difference between the current value and the previous value, and the "slope" is the change amount / ( Store the current time-previous value input time).

FIG. 5 is a calculation flowchart of the change point start point detection section 61. This calculation flowchart is for calculating the maximum amount of change after detecting a sudden change in frequency or interconnection power flow. Here, what is limited to the frequency or interconnection power flow is that, as shown in FIG. 17, when an accident occurs, the frequency and interconnection power flow information is transmitted first, and then, after several seconds to several minutes, the total This is because the generated power and total demand power are sent.

First, one of the electric power companies is designated (611). Then, it is checked whether or not the start point of the change point, that is, the start point of the abrupt change is already detected based on the element information indicating the deviation (612). If any of the element information, in this case, the frequency or the interconnection flow, changes suddenly, it takes time to complete all the changes of the other element information as described with reference to FIG. Therefore, in the present invention, after detecting the first sudden change, the accident detection timer, which is a waiting time until the state changes of other element information are completed, is operated, and in conjunction with this timer operation, "change point start point detected ", The flag is set. That is, when the change point start point has been detected, it indicates that some sudden change in element information has already been detected and is waiting for the time-up of the accident detection timer.

When the change point start point is not detected,
This represents a state in which the first sudden change has not been detected yet, and the presence or absence of a sudden change is checked by executing the processing 613 and subsequent steps. That is, the frequency change Δf and the interconnection line power flow change Δp are calculated from the difference between the current value and the previous value (613), and the frequency Δf or the interconnection line power flow change Δp is a reference value for determining a sudden change. If it has changed to K1 or K2 or more (614616), it is determined that the change point start point is detected, and the following processing is performed.

The "change time", "size before change", "change amount", and "gradient" are stored in the change amount table shown in FIG. 4 (615, 617). Then, the change point start point detected flag is set, and an accident detection waiting timer, generally a timer having a time period of 2 to 3 minutes set, is started (618), and calculation is performed for all electric power companies (619). .

As a result, when either the frequency or the power flow on the interconnection line suddenly changes, the waiting timer until the accident is detected starts operating. When this timer times out, the accident detection unit 70 detects whether or not an accident has occurred based on the amount of change in each element information that has occurred during the timer operation period, that is, the gradient.

Next, FIG. 6 is a calculation flowchart of the maximum change amount calculation process 63 in the change amount calculation unit 60. When the determination in the change point start point detection determination processing 62 of the change amount calculation unit 60 has not yet detected the change point start point, that is, for each element information that has occurred while the accident detection timer is running and the time is up. The maximum change amount of is captured in the maximum change amount calculation process 63. First, a power company is designated (631), and element information within the power company is designated (632). Then, it is checked whether the specified element information has already detected the change point start point (63
3). This means that the change points of the frequency, the interconnection point power flow, the total power generation, and the total power demand shown in FIG. 17 are detected.

Whether or not it has been detected can be known by looking at the change time of the element in the change amount table of FIG. That is, if the change time has been stored, the change point start point has already been detected for each piece of element information. If the change point start point is not detected,
The difference ΔX between the current value and the previous value is calculated (634), and if this is greater than or equal to the specified value Kx (635), the next large variation is written in the variation table of FIG. 4 (636).
That is, the previous value input time as the “change time”, the previous value as the “size before change”, the difference ΔX between the current value and the previous value as the “change amount”, and the change amount / (previous value input time as the “slope” ) Are respectively written in the variation table.

When the change point start point has been detected, the difference ΔY between the current value and the size before the change is calculated (637), and this is compared with the change amount stored in the change amount table (63).
8) If ΔY is larger, the change amount column of the change amount table is replaced with ΔY (639). As a result, the maximum change amount is detected. Then, when all the elements in the electric power company are completed (640), the same calculation is performed for other electric power companies (641).

FIG. 7 is an explanatory diagram of an example of calculation of the amount of change when the frequency drops. When a power loss accident occurs, the frequency immediately drops sharply. Each generator increases its output all at once in response to this decrease in frequency, so the maximum decrease occurs in about 5 to 6 seconds after the accident, depending on the scale of the system. And
After 10 seconds, the original frequency is restored. In Fig. 7, the frequency was 50Hz, but due to power loss at the change time 0s,
The frequency is lowered, and the accident detection device 11 detects 0.
A change of 15 Hz is detected, and the maximum change amount of 0.
The case where 35 Hz is detected is shown. That is,
When a frequency change is detected at the current time 1 s, the change time is 0 s, the magnitude before the change is 50 Hz, and the current value is 4
It becomes 9.85 Hz, and the maximum change amount is detected at the time point 2s.

Next, when the accident detection timer times out, the accident detection unit 70 refers to the table of FIG. 4 to detect whether or not an accident has occurred in the power company. Is either a power loss accident or a load loss accident. In the power loss determination processing 71 of the accident detection unit 70, it is determined whether or not there is a power loss accident.

FIG. 8 is a case example flow chart in the power drop determination processing 71. Here, the element information of the power company is taken out from the change amount table of FIG. 4, and it is determined whether or not the power source is dropped based on this. First, the electric power company is designated (711) and whether the frequency drop is steep, that is, the slope is large (712), or the inflow of interconnection power flow increases rapidly (the slope is large).
If so (713), it is determined that an accident may occur, and it is further checked whether or not the total generated power has decreased to a specified value or more (714). If this condition is satisfied, it is determined that the power company has a power loss accident. When it is determined that the power supply has been dropped, the time, the name of the power company, the aspect of the accident (power drop), and the scale (decrease in total power generation) are stored for output (display) (715). Then, the same calculation is performed for all electric power companies (716).

In the load drop judgment processing 72 of the accident detection section 70, it is judged whether or not there is a load drop accident. FIG. 9 is a flowchart of load drop determination in the load drop determination process 72 of the accident detection unit 70. Similar to the case of power loss, the element information of the power company is extracted from the change amount table of FIG. 4, and based on this, it is determined whether or not the load is dropped. First, an electric power company is designated (721), and if the frequency rises sharply (the gradient is large) (722), or if the interconnection power flow sharply decreases in the inflow direction (the gradient is large) (723), an accident occurs. Then, it is checked whether the total power demand has decreased more than the specified value (724).

If this condition is satisfied, it is determined that a load drop accident has occurred at the power company. When it is determined that the load has dropped, the time, the name of the power company, the appearance of the accident (power drop), and the scale (decrease in total power generation) are stored for output (display) (725). Then, the same calculation is performed for all electric power companies (726).

When the output processing unit 80 detects a power loss accident or a load loss accident, the alarm output processing 81 detects the details of the accident, that is, the time of occurrence, the power company, the aspect of the accident (power loss, load loss) scale (MW). ) Is output as an alarm and is displayed on the display device in the display display processing 82.

By periodically executing the above processing, it is possible to detect a power loss or load loss accident from the change amount and change direction of the element information, and notify the operator of the accident content together with an alarm.

Next, a second embodiment of the present invention will be described.
First, the situation of the system will be described. In normal grid operation, proper operation is performed so that the generator stoppage or disconnection does not cause disturbance in the grid, so both the total generated power and the total demanded power move gently, but in the event of an accident these are large. Change. When the power source and the load are dropped at the same time, both the frequency and the power flow in the interconnection line change greatly, but the direction (increase / decrease direction) is uncertain, and finally the total generated power and the total demand power also greatly decrease. The second embodiment utilizes this feature.

In other words, in the second embodiment, the power supply simultaneous load drop judgment processing 7 for detecting that the power failure accident and the load loss accident occur simultaneously in the accident detection unit 70 of the first embodiment.
5 is added. FIG. 10 is a calculation flowchart of the accident detection unit 70 in the second embodiment. After the power drop determination processing 71 and the load drop determination processing 72, the power load simultaneous drop determination processing 75 is performed. First, an electric power company is designated (751), and it is determined whether or not the amount of decrease in total power generation is larger than a predetermined specified value K3 (752). If the result of determination is that the amount of decrease in total generated power is larger than a predetermined specified value K3, it is similarly determined whether the amount of decrease in total power demand is larger than a predetermined specified value K4 (75
3). That is, it is checked whether it is a change in normal operation or a big change that can be judged as an accident, and if it is judged as an accident, the output time, the name of the power company, the appearance of the accident (simultaneous disconnection of the power load) are output information. ), Memorize the scale of the accident (754). Then, the process for the previous electric power company is performed (755), and when the process for all the electric power companies is completed, it is determined whether or not the accident can be detected (73),
If the accident can be detected, the process goes to the output process 80, and if not, the process goes to the CDT input process 50. According to the second embodiment, it is possible to detect a power supply load simultaneous dropout accident.

A third embodiment of the present invention will be described with reference to FIG. In the third embodiment, each electric power company is notified of the accident information of the accident detected by the accident detection device 11 in the first and second embodiments.
This notification is transmitted to each electric power company using a transmission device provided outside. There are various transmission devices such as a CDT device that connects the medium-paid station 6 to each electric power company, or a computer system network, but data transmission between the medium-paid station 6 and each electric power company is possible. Any method is acceptable as long as it is.

In FIG. 11, in addition to the one shown in FIG. 1, a transmission device 15 for each electric power company is installed, and the accident information transmitted from the accident detection device 11 is transmitted to each of the transmission lines 5 via the transmission line 5. It is transmitted to the mid-payment 3 of the power company. Medium pay side transmission device 1
5 outputs the received accident information to the display 16. 12
Shows the processing contents of the output processing unit 80 according to the third embodiment, and is added with the processing 83 for outputting the accident information to the newly installed transmission device 15. In this process 83, accident information for all electric power companies is output. In the third embodiment, the accident information is transmitted to each electric power company, which facilitates the operation of the interconnection system.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment differs from the first and second embodiments in that it calculates a prescribed value K1 used when determining the magnitude of the frequency change amount according to the national total power demand at that time. Is added. In FIG. 12, an input device 411 is an input device for setting a verification target value, that is, the magnitude of the power dropout that should be judged as an accident. In this fourth embodiment, a CRT display device is used. In the target value input processing 412, the test target value for each electric power company input from the input device 411 is read and stored in the target value storage file. This input processing 412 is 2 to 2 times a year.
It is performed about 3 times.

Process 414 is the total power demand in the whole country, that is,
This is the sum of the total power demands of all power companies, and is the total power demand of each company sent from each intermediate supply.
However, the total demand of electric power companies that are disconnected from the interconnection line and become a single grid is not included in the total. The calculation process 414 of the nationwide total power demand is generally performed every 15 minutes, but may be performed each time the change amount calculation unit 60 operates.

Next, the process 415 is the process 61 shown in FIG.
Specified value K used when determining whether there is a frequency change in 4
1 is calculated by the following formula based on the test target value of the target value storage file 413 and the calculated national total power demand.

K1 = ΔP / K * P1 (Hz) where ΔP; verification target value (Hz) K; system constant (% MW / 0.1Hz) P1; national total power demand (Hz)

By using K1 calculated as described above, the change amount calculation processing unit 61 can keep the magnitude of the lost power determined as an accident constant even if the nationwide total power demand fluctuates. In addition, for an electric power company that has a single grid due to an interconnection line accident, the nationwide total power demand P1 is only the total power demand for the company.

[0057]

As described above, according to the present invention, it is possible to realize a system fault with high reliability from a change amount of element information such as frequency and in a short period of time. This allows
Only systematic accidents caused by operators are eliminated and the ambiguity of judgment is eliminated. Further, even when a power loss accident and a load loss accident occur at the same time, the accident can be detected, so that the utility of the system accident detection device can be improved.

On the other hand, since the system accident information is notified to each electric power company, it becomes possible to give advance notification to each electric power company before supporting the emergency support, whereby each electric power company also prepares for an early accident response. It enables quick power interchange. Also, because the specified value that is the target for the dropout is calculated according to the total power demand in the whole country at that time, the frequency limit value at the time of an accident detection should be automatically adjusted according to the change in the power demand in the whole country. become. Therefore, the operator does not have to worry about the change in sensitivity due to the amount of total power demand in the whole country.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram in which the accident detection device of the present invention is applied to an interconnection system.

FIG. 2 is an explanatory diagram of an accident detection device according to the present invention.

FIG. 3 is an explanatory diagram of an input value table of the present invention.

FIG. 4 is an explanatory diagram of a change amount table according to the present invention.

FIG. 5 is a calculation flowchart of change point start point detection processing of the present invention.

FIG. 6 is a calculation flowchart of maximum change amount calculation processing of the present invention.

FIG. 7 is an explanatory diagram of a calculation example of the amount of change when the frequency decreases.

FIG. 8 is a determination flowchart in the power supply drop determination process of the present invention.

FIG. 9 is a flowchart of load drop determination in the load drop determination process of the present invention.

FIG. 10 is a calculation flowchart of the accident detection unit according to the second embodiment of the present invention.

FIG. 11 is an overall configuration diagram in which an accident detection device showing a third embodiment of the present invention is applied to an interconnection system.

FIG. 12 is a flowchart showing the processing contents of the output processing unit according to the third embodiment of the present invention.

FIG. 13 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 14 is an explanatory diagram of a relationship between medium-paid and medium-paid grid in each electric power company connected by an interconnection line.

FIG. 15 is an explanatory diagram of information transmission between the power station and substation and the medium-price salary, and between the medium-salary salary and the medium-paid ream in each electric power company.

FIG. 16 is an explanatory diagram of a generator dropout accident in the interconnection system.

FIG. 17 is a transmission time chart to the intermediate feeding station 6 when the large capacity generator is dropped.

[Explanation of symbols]

 1 Power Company 2 Interconnection Line 3 Central Power Supply Command Center 4 CDT Device 5 Transmission Line 6 Central Power Supply Liaison Office 7 Substation 8 Monitoring Panel Control Device 9 Meter 10 Paper Chart Recorder 11 Accident Detection Device 12 Display Device 15 Transmission Device 16 Display Unit 50 CDT input processing unit 60 Change amount calculation unit 70 Accident detection unit 80 Output processing unit

Claims (6)

[Claims] 1. An element periodically transmitted from a central power supply station of each of the power companies of the grid interconnecting system in which the power systems of a plurality of power companies are interconnected and power is exchanged between the respective power companies. In an interconnected system accident detection device that detects an accident in the electric power system of each of the electric power companies based on information,
A CDT input processing unit that periodically inputs the element information and stores the input current value and the previous value, and compares the current value and the previous value with respect to the frequency and the interconnection line flow of the input element information. When the sudden change is detected, a change amount calculation unit that calculates the change gradient, and a power loss accident and a load loss accident are detected based on the total power generation and the total demand power among the element information and the frequency change gradient. An interconnected system accident detection device comprising an accident detection unit. 2. The accident detection unit, when the change gradient of the decrease in the frequency is steeper than a predetermined set value and the decrease in the total generated power in the element information is larger than a predetermined set value. Is a power loss accident, and if the change gradient of the increase in the frequency is steeper than the preset value and the decrease of the total power demand in the element information is abrupt, it is determined to be the load loss accident. The accident detection device for an interconnected system according to claim 1, wherein: 3. The accident detection section is provided with a power load simultaneous drop detection function for detecting that both the power drop accident and the load drop accident have occurred in a power system within the same power company. The interconnected system accident detection device according to claim 1 or 2. 4. The power supply load simultaneous drop detection function detects the power drop accident when the decrease amount of the total generated power is larger than a predetermined set value and the decrease amount of the total demand power is larger than a predetermined set value. The accident detection device for the interconnection system according to claim 3, wherein it is determined that both the load drop accident has occurred. 5. The interconnection system according to claim 1, wherein the accident detection result of the accident detection unit is transmitted to a central power supply command station of each of the electric power companies. Accident detection device. 6. The predetermined set value of the frequency change gradient in the accident detection unit is set based on the total power demand of the entire interconnection system. 5. An interconnected system accident detection device according to item 5.