JPS627763B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a protection arithmetic processing device for a fully automatic synchronized digital system in an electric power system, and particularly to a protection arithmetic processing device for performing back-up protection in a part of a low-speed processing mechanism for digital data processing. The present invention relates to a protective relay device.

Furthermore, in the process of information flow of digital electricity from the high-speed data processing mechanism section to the low-speed data processing mechanism section, the present invention provides a circuit that is independent of the high-speed data processing mechanism section at the contact point between the two data processing mechanism sections. The system is designed to perform backup protection operations.

Although digital electrical quantities are superior to analog electrical quantities in terms of storage, time division, and high-speed arithmetic processing, they are inferior in terms of temporal redundancy. Devices that utilize digital electricity have drawbacks, but because of the advantages described above, digital protection devices are increasingly being used.

The present invention has been made in view of this point, and is intended to improve the drawbacks of temporal redundancy and reduced reliability of the digital system.

Here, the disadvantage of temporal redundancy in the digital system means the following.

That is, analog quantities are continuous quantities, and when considered on the basis of this, digital quantities are discrete quantities.

Therefore, there is no correlation between the current digital amount and the digital amount one sample ago. This means that if we assume that the input amount follows a sine (or cosine) function, and if we sample at regular intervals, we can find a predetermined relationship between the current digital amount and the digital amount one sampling ago. Become. If the data is disturbed by instantaneous noise etc. during the analog/digital conversion process, in order to identify this, it is necessary to update the data until it is determined that the data on the sine (or cosine) wave is available. It is necessary to wait for the arrival of appropriate data.

Based on the comparison with the analog system, this is tentatively referred to as the disadvantage of temporal redundancy of the digital system.

FIG. 1 is a diagram showing an outline of the system configuration that is the background of this invention. The same reference numerals in the diagram indicate devices having the same functions, and a two-terminal power transmission system is described as an example. . To distinguish both ends of the power transmission line, they are referred to as the first end (end A) and the second end (end B), and in Figure 1, the subscripts A and B are added to distinguish the equipment belonging to both ends. be.

In the figure, 1 is a generator, 2 is a bus bar, and 3 is a sensor, and the voltage and current sensors are shown as one in the figure. 4 shows a device that converts the analog electrical quantity of the system into a digital electrical quantity and performs sampling to clarify the sampling time. 5 is a sending device for transmitting this digital quantity of electricity, and the quantity of electricity that needs to be converted into a digital quantity of electricity is the positive phase 3.
There are a total of four quantities for voltage and current, one quantity and one zero phase quantity, and the analog-to-digital converter is shown as a representative phase in the diagram, but in actual use, it is prepared for eight quantities. Needless to say, the sending device 5 orders these digital quantities in a predetermined order, and also records the open/closed state of a shear disconnector, etc. installed near the sensor 3, within the sending device 5. The information is converted into ON/OFF information and sent out in a predetermined data transmission format along with the above-mentioned digital amount. 6 is the transmission line 7 is a receiving device, 8 is a data yard with an address that integrates and distributes digital electricity, and 9 is a receiving device for digital information sent from the other end.
is reassembled into a new predetermined data transmission format that integrates the own end information (including numerical information and ON/OFF information) and the other end information (including numerical information and ON/OFF information) from the receiving device 9, and then transmits the data. The data is distributed to the high-speed processing device 16 connected to the way 13, the transmitting device 12, etc. Reference numeral 10 denotes a receiving antenna, and information at the other end is usually transmitted by microwave. Reference numeral 11 denotes an antenna for transmitting the digital electricity amount at the own end to the other end, and 12 is the transmitting device for transmitting the information at the own end in the data way 13 (details of the information flow are shown in Figure 2) and the other end. Data for the other end electrical station is selected and transmitted from the information containing the information. 13 is a data way that transmits the digital electricity output from the integrated distribution data yard;
4 and 15 collect necessary data from the addresses of these digital electricity quantities and perform protection calculation functions according to a predetermined program. For example, 14 controls power transmission line protection, and 15 controls busbar protection (details are in Section 4). (Described later in Figure 2). These perform calculations using momentary instantaneous values (synchronous sampling data). 16 is commonly called a high-speed processing device because it performs calculations using these synchronous sampling data. Reference numeral 17 is a newly provided data primary processing device which is the main subject of the present invention, and performs primary processing by determining the address of synchronous sampling data. In other words, for the purpose of measurement, recording, etc., these results are transferred to a low-speed processing device, and the magnitude of voltage V, the magnitude of current I,
In order to derive active power, reactive power, etc., the phase difference θ between the voltage and current of each corresponding phase is also calculated. This belongs to the range of high-speed processing equipment as it determines the address and collects synchronous sample data, but it is the point of contact with the low-speed processing equipment that is the core of the man-machine interface. We will treat them separately here.
Reference numeral 18 denotes a low-speed processing device, and the administrator uses this device to manage this system (including measurement, recording, and although not shown, changes to tap values of the high-speed processing device 16, and display of these). ) and is in charge of all information gathering and commands within the electrical station. 19
is the power transmission line connecting the A end and B end, 20 is the circuit breaker,
21 is an integrated distribution device for circuit breaker trip signals output as calculation results from the high-speed processing devices 14, 15, and 16; 22 is a trip output of this integrated distribution device 21; (not shown). 23 is the first end (A end)
The same equipment as described above is installed at the second end (B
This indicates that it is installed at the edge). FIG. 2 is a diagram showing an example of the flow of information in this system, and the same numbers as in FIG. 1 indicate the same items.
In the figure, numeral 31 is a voltage transformer PD, 52a is a status display contact of a disconnector 20, and the power transmission line 19 is composed of three phases, A to C phases.

One set of analog/digital electrical quantity converters 4 is arranged for each phase. In the figure, a case is shown in which a total of six quantities, each of three quantities, current and voltage, are sampled at the same time. The output of the analog/digital electrical quantity converter 4 is sequentially multiplexed and read by the sending device 5, but the data is protected for a sufficient period of time. This sending device 5 may multiplex not only digital data but also switch status information. Data sent through the transmission line 6 reaches the receiving device 7. Second
Although the figure shows the voltage and current for one system, the voltage and current for other systems will be sent through the transmission lines 61 to 6n as described above. All the information of the electric station is sent through the transmission lines 6, 61, . . . , 6n, and it goes without saying that all the data is sampled at the same time. It goes without saying that a plurality of sets of receiving apparatuses 9 are required if there are a plurality of adjacent electrical stations. At this time, the data of the adjacent electric station is also sampled at exactly the same time by another transmission device (not shown).

If you collect data like this, data yard 8
will have all the data necessary to protect/control. Therefore, data necessary for protection control is constantly flowing through the data way 13. Therefore, for example, in the bus protection high-speed processing device 15, if a procedure is determined to read the required current data by reading the address of the data flowing through the data way 13, the data necessary for bus protection can be collected. I can do it. Here, an outline of the operation of the present invention for protecting the power transmission line 19 will be described.

In FIG. 1, the power transmission line 19 is protected by a high-speed processing device 14 (designated by MDP and called a micro data processor). This is because both the first and second ends are sampled in synchronization, and there is a transmission delay in data from the other end, so if, for example, current differential protection is to be implemented, it is necessary to synchronize these times. can be,
In order to make this possible, it is necessary to attach a sample to the device 4. A synchronizing signal is given to all ends, a sampling number is added based on this signal, and this sample number is checked and the high-speed processing device
It is possible to check the data of the own end and the other end within the MDP.

Now, if this is the main protection, the same high-speed processing device
Of course, it is possible to provide backup protection with MDP, but a time delay of 0.1 to 0.2 seconds is required before the backup protection outputs in order to coordinate with the main protection. The high-speed processing device 14 is a plurality of high-speed processing devices.
Of course, it is possible to perform main protection and backup protection for the MDP complex, but this will be difficult if the number of lines increases.
Inevitably, the amount of hardware (H/W) will increase, and if a failure occurs in the high-speed processing device MDP, there is a high risk that both primary protection and backup protection will be lost, which is too much from an economical and reliability standpoint. It can no longer be said that it is a good idea.

This invention was made in view of this point, and is intended to dramatically increase economic efficiency and reliability.

Since the output of the device 17 is used to control the low-speed processing device 18, there is no need to output an output every sampling period like the high-speed processing device 16, and the device 17 has a size that is large enough to make it easy for the low-speed processing device 18 to perform calculations. Since the phase difference is calculated by primary processing, there are many advantages if back-up protection is performed here. That is, from the device 17 to the output to the low-speed processing device 18
A time delay of 0.1 seconds to 0.2 seconds is allowed. Therefore, time-sharing processing, which is the most distinctive feature of digital processing devices, becomes possible.

For example, if the input waveform of the relevant phase of the relevant line is sampled every 30 degrees in electrical angle by an analog/digital converter and converted into a digital quantity, then Needless to say, the phase data is stored every 30 degrees of electrical angle. At this time, if data is thinned out and passed to the low-speed processing device 18 every 30°N (N = 1, 2, 3...) and an algorithm suitable for this data string is assigned, in principle backup protection processing for N phases can be performed. This can be considered equivalent to possessing the ability. Therefore, even if the number of lines increases, there is no direct need to increase the hardware (H/W) as mentioned above, and the main protection and backup protection are completely independent from the hardware. A further feature is that the main protection and its algorithm (processing symbol) can be made completely different because data that has necessarily been partially processed is reused. By doing this, the algorithm of the high-speed processing device and the low-speed processing device and the data used can be used to solve situations where tripping is impossible due to data disturbance due to electromagnetic field disturbance, such as a system accident where you want to obtain a tripping signal for a circuit breaker. This can be avoided since it is possible to make the . This is one way to improve the drawback of temporal redundancy mentioned at the beginning. Of course, high-speed processing device 1
6, it is possible to use different algorithms for main protection and backup protection, but this only provides a certain sense of redundancy in the software (S/W), and it is not possible to use traditional main system protection. Considering that the device completely separates the main protection and back-up protection, this cannot be said to be a sufficient measure in terms of the reliability of the device.

Furthermore, there is a method of completely separating the hardware (H/W) and software (S/W) by using a large number of high-speed processing devices MDP within the device 16.
In this method, hardware (H/
W) is required, and the increase in the number of semiconductor elements significantly reduces the reliability of the device, making it difficult to employ time division, which is a characteristic of digital processing, and is no longer a good idea.

According to the present invention, a primary processing device is provided between the low-speed processing device 18 and the information flow, and the results of this primary processing are used as backup protection algorithm data, so hardware (H/W) and software ( S/W) can be completely separated. Since time-division processing is thus possible, an increase in the number of elements can also be prevented.

Here, in accordance with the gist of the present invention, if a primary processing device is provided between the data way 13 and the low-speed processing device 18 and backup protection is performed here, an outline of the algorithm will be as follows. Become.

That is, since the voltage, current, and phase difference thereof are prepared for each line, it is possible to use these to create an impedance relay in which the impedance is expressed in polar coordinates.

In the embodiment of the present invention, a differential relay is assumed as the power transmission line protection relay device.

Therefore, since it is a differential current relay, it is necessary to compare the magnitudes at both ends, and for that reason, current data at one end is transmitted to the other end. Further, although not shown, there are not only 19 power transmission lines but also other power transmission lines connected to the bus 2-A at the A end. Therefore bus line 2
- All power lines and generators connected to A1
A current sensor is installed on the connection line between -A and bus 2-A to detect the current. Sensor 3-
The outputs of the sensors other than A are converted into digital data by an analog-to-digital converter and then passed through the data yard 8 and inputted to the protection calculation function 15, so the protection calculation function 15 calculates the sum of the current flowing into the bus 2-A. The difference in the total sum of flowing currents is determined, and if the difference is greater than a set value, it is determined that there is an internal failure in the bus 2-A, and a trip command is output. Therefore, the protection calculation function 15 can protect the bus bar.

As is clear from the above explanation, in the present invention, a digital data primary processing device is provided between the data way and the low-speed processing device, and backup protection is provided here, so that hardware (H/
It becomes possible to completely separate W) and software (S/W), which eliminates the need to provide backup protection for each line, and enables time-division processing, which is a feature of digital processing devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the protective relay device of the present invention using an all-end automatic synchronization digital system, and FIG. 2 is an explanatory diagram showing the flow of information in FIG. 1. In the figure, 13 is a data way through which digital data is transmitted, 14 and 15 are high-speed arithmetic processing units, and 17
18 indicates a data primary processing unit, and 18 indicates a low-speed arithmetic processing unit.

Claims (1)

[Claims] 1. In a power system having at least a first end and a second end, a first sensor and a second sensor for converting outputs responsive to the voltage and current of the first end and the second end into digital quantities of electricity. and a transmission device for respectively transmitting the digital electricity amount from the first end to the second end and from the second end to the first end, and the digital electricity amount transmitted from the other party's sensor and the digital electricity at the own end. A data yard that integrates and distributes the amount of electricity, and a data way that transmits the output from this data yard, determines the address, collects and stores the necessary digital electricity amount, and processes this stored digital electricity amount with a predetermined algorithm. and a main protection processing unit that performs the protection calculation function by determining the address from the data way, collecting and storing the necessary digital electricity quantity, and processing this stored digital electricity quantity with a predetermined algorithm to perform the protection calculation function. In an all-end automatic synchronous digital system equipped with a low-speed processing device that performs A protective relay device characterized by performing the following.