CN103746304B - The remodeling method of Intelligent transformer station - Google Patents

Abstract

The invention discloses a transformation method of an intelligent substation, and the technical problem to be solved is that the busbar does not lose protection operation during the transformation of the intelligent substation. The method of the present invention includes the following steps: transfer and connect the secondary cables of each bay of the bus differential protection of the traditional substation to the sub-unit of the digital bus differential protection, electrically connect the bay merging unit and the intelligent terminal with the primary equipment of the substation through cables, and modify the digital bus differential protection Poorly protect the communication parameter settings of the master, and remove the slave. Compared with the prior art, the present invention adopts the digitalized bus differential protection master and the digital bus differential protection sub-machines used in the intelligent substation to share in the transformation process, and the transformation process does not affect the protection operation mode and load distribution of the whole substation, reducing The power outage time of the equipment during the transformation period is reduced, and the transformed equipment only needs to be powered off once, the exit time of the bus differential protection is short, the reliability of the power grid operation is high, the construction difficulty is reduced, the work efficiency is improved, and the investment is small.

Description

Transformation method of intelligent substation

technical field

The invention relates to a construction method of an intelligent substation, in particular to a method for transforming an intelligent substation by adopting digital bus differential protection.

Background technique

With the further promotion of intelligent substation construction and the wide application of digital protection, the engineering application of digital protection in the construction and transformation of intelligent substations is one of the key points in the construction of intelligent substations. The importance and particularity of digital busbar protection, protection range and application conditions occupy an extremely important position in the engineering application of intelligent substations. Since the intelligent substation uses optical fiber to transmit digital information, it greatly reduces the cable wiring workload in the substation, shortens the installation and commissioning cycle of the intelligent substation, and can realize the on-line monitoring of the relay protection device and the secondary circuit. Provide reliable technical support. In the existing method of transforming traditional substations into smart substations, since all bus intervals cannot be transformed at one time, the bus differential protection device will not be able to collect complete bus information during the transformation, and the protection of the bus needs to be suspended, which brings power to the power supply. Security risks.

Contents of the invention

The purpose of the present invention is to provide a method for transforming an intelligent substation, and the technical problem to be solved is that the busbar does not lose protection operation during the transformation of the intelligent substation.

The present invention adopts the following technical solutions: a method for transforming an intelligent substation, comprising the following steps:

1. Information collection, transmission and switching. The transformed traditional substation is equipped with a digital bus differential protection host, and each digital bus differential protection sub-machine is connected to 1-12 bays, and the secondary cables of the traditional substation bus differential protection for each bay are connected. Transfer and connect to the digital bus differential protection sub-machine, the digital bus differential protection sub-machine receives the binary input of the connected interval, according to 80 points per cycle, samples the alternating current and voltage of the connected interval, and converts the alternating current It is a digital quantity, and the binary input quantity and digital quantity are transmitted to the digital bus differential protection host through optical fiber;

2. After receiving the binary input quantity and digital quantity sent by the digital busbar differential protection sub-machine, the digital bus differential protection master judges the operation mode of the bus according to the binary input quantity of each interval, and processes the digital quantity according to the bus protection criterion. Realize the real-time protection of the busbar;

3. For the power failure of the primary equipment in the interval, the interval merging unit and the intelligent terminal are electrically connected to the primary equipment of the substation in the interval through cables, and then the merging unit and the intelligent terminal are connected to the digital bus difference protection host through optical fiber, and put into the primary equipment;

4. For the bays that have completed the intelligent transformation, modify the communication parameter settings of the digital bus differential protection host, so that the collected bay input and exchange volumes are switched from the digital bus differential protection sub-machine to the merging unit and intelligent terminal. Realize the switching of collecting information at the transformation interval;

5. The main unit of digital bus differential protection is connected to the merging units and intelligent terminals of all intervals, and all sub-units are removed to complete the transformation of the intelligent substation.

In step 1 of the method of the present invention, the digital bus differential protection sub-machine receives the output information sent by the digital bus differential protection host, and the digital bus differential protection host sends out a protection action signal, and realizes a switch trip through the output relay of the digital bus differential protection sub-machine .

The digital bus differential protection sub-unit of the method of the present invention receives the GOOSE tripping message sent by the digital bus differential protection host and analyzes the message according to the format specified in the IEC61850 standard, and obtains the action command currently issued by the digital bus differential protection host. When the GOOSE report In this paper, when there is an interval set trip exit command, the exit command is sent out to control the corresponding exit relay exit trip.

Step 2 of the method of the present invention, the digital bus differential protection host sends the bus differential protection operation information to the automatic monitoring system located in the main control room, so as to realize the remote monitoring of the bus differential protection by substation operators; the digital bus differential protection host stores the bus differential Protection operation information; the bus differential protection operation information is information on binary input, digital quantities, and communication conditions between the master and the slaves received by the master.

Step 3 of the method of the present invention After putting into the primary equipment, the merging unit and the intelligent terminal send the digital quantity and input quantity of the AC quantity of the collected current and voltage to the digital bus differential protection host, and carry out transformation at each interval to connect the merging unit During the communication with the intelligent terminal, the main unit of the digital bus differential protection still receives the binary input quantity of the transformed interval and the digital quantity of the exchange volume collected at 80 points per cycle through the digital bus differential protection sub-machine, and sends it to the main unit for the merging unit and the intelligent terminal The digital quantity and binary input quantity will not be processed.

Before the step 4 of the inventive method modifies the communication parameter setting of the digitized bus difference protection host computer, test is carried out, and the test method is:

Test the synchronization between the digital bus differential protection sub-machine and the merging unit. The merging unit and the digital bus differential protection sub-machine send the digital quantity of AC volume collected at 80 points per cycle to the digital bus differential protection host at equal intervals. The digital bus differential protection The protection host adopts interpolation synchronization method for processing;

For the bus differential protection configuration test, use an analog tester to simulate the intelligent terminal, merging unit, and digital bus differential protection sub-machine or simulate the site with the digital bus differential protection host and the intelligent terminal, merging unit, and digital bus differential protection sub-machine before transformation Connect through optical fiber, and download the configuration file to the intelligent terminal, merging unit, and digital bus differential protection sub-machine, and check whether the communication between the intelligent terminal, merging unit, digital bus differential protection sub-machine and digital bus differential protection host is normal, Simulate adding binary input and AC volumes to the digital bus differential protection host to check whether the digital bus differential protection host can receive the message correctly, and send out the trip information and alarm information correctly after the alarm and action.

In Step 4 of the method of the present invention, the intelligent terminal of the transformed interval sends input in real time, and the merging unit performs sampling of the alternating current and voltage of the interval at 80 points per cycle, and sends the analog-to-digital conversion to the digital bus differential protection host.

The digitized bus difference protection sub-machine of the method of the present invention collects the alternating current and voltage of multiple intervals, and the alternating current sampling data obtained after analog-to-digital conversion is combined together, and the alternating current sampling at different intervals is sampled through a difference sampling algorithm The data is time-synchronized, and then the combined and synchronized AC sampling data at each interval is packaged into a frame according to the IEC61850-9-2 protocol, converted into an optical signal, and the message containing the AC sampling value information is sent to the digital bus through the optical fiber connection Protect the host.

The digitized bus difference protection sub-machine of the present invention collects multi-interval binary input signals, converts them into digital information, packs the selected binary input quantities according to the GOOSE message format stipulated in the IEC61850 standard, converts them into optical signals, and transmits them through optical fiber connections. The message containing binary input data is sent to the digital bus differential protection host.

Step 1 of the method of the present invention, for the dual traditional bus difference protection configuration, one set of traditional bus difference protection configuration is always put into operation, another set of traditional bus difference protection configuration is withdrawn from operation, and each interval before the withdrawn traditional bus difference protection configuration is The AC quantity of the circuit, the terminals of the binary input and binary output cable connections are sequentially connected to the digital bus differential protection sub-machine;

For the single-duty traditional bus differential protection configuration outdoor circuit breaker, the secondary side of the transformer has the AC volume required for the bus differential protection, the spare contacts of the input and output, and connect the spare contacts to the digital bus differential protection through the cable Sub-machine, do not withdraw from the existing traditional bus differential protection;

The AC volume, binary input and output required for the configuration of traditional bus differential protection. If there is no spare contact, exit the traditional bus protection, and the AC volume, binary input and output of each interval circuit connected before the exiting traditional bus differential protection device Connect the terminals of the measurement cable to the sub-machine in sequence.

Compared with the prior art, the present invention adopts the digital bus differential protection master and the digital bus differential protection sub-machines used in the intelligent substation to share in the transformation process, and the transformation process does not affect the protection operation mode and load distribution of the whole substation, reducing the The power outage time of the equipment during the transformation period is shortened, and the transformed equipment only needs to be powered off once, the exit time of the bus protection is short, the reliability of the power grid operation is high, the construction difficulty is reduced, the work efficiency is improved, the investment is small, and only the digital bus difference needs to be increased To protect the sub-machine, the digital bus differential protection sub-machine can be used repeatedly.

Description of drawings

Fig. 1 is a wiring diagram of the digital bus differential protection main unit and the digital bus differential protection slave unit according to the embodiment of the present invention.

Fig. 2 is a connection diagram of the digital bus differential protection host during the transformation process of the embodiment of the present invention.

Fig. 3 is a connection diagram of the digital bus differential protection main unit after the transformation of the embodiment of the present invention is completed.

Fig. 4 is a schematic diagram of 1588 clock synchronous timing correction according to the embodiment of the present invention.

Fig. 5 is a circuit block diagram of a digital bus differential protection sub-machine according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of the interpolation synchronization method.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. The transformation method of the intelligent substation of the present invention adopts the digitized bus difference protection main machine (main machine) and the digital bus difference protection sub-machine (sub-machine) used in the intelligent substation to share in the transformation process, including the following steps:

1. Information collection, transmission and switching. Each transformed traditional substation is equipped with a host computer. Before the traditional substation is intelligently transformed, as shown in Figure 1, according to the actual number of intervals in the transformed traditional substation, each slave computer is connected to 1 -12 intervals, so the transformed 110kV traditional substation can be equipped with 1-3 sub-units, transfer and connect the secondary cables of each compartment of the bus differential protection of the traditional substation to the sub-units, and the sub-units will collect and transmit information to the host computer to realize information Acquisition switching, each sub-machine receives the binary input of the connected interval, and samples the alternating current and voltage (alternating current) of the connected interval according to 80 points per cycle, and converts the sampled alternating current into digital The digital quantity is transmitted to the main unit through the optical fiber; at the same time, the sub-unit receives the output information sent by the main unit. Once the main unit sends a protection action signal, it will realize a switch trip through the output relay of the sub-unit.

2. After receiving the binary input and digital quantities sent by the sub-machine, the master judges the operation mode of the transformed traditional substation busbar according to the binary input quantities of each interval, and normally processes the digital quantities according to the busbar protection criteria to realize For real-time protection of the bus, the operation information of the bus differential protection is sent to the automatic monitoring system located in the main control room to realize the remote monitoring of the bus differential protection by the substation operators, and the operation information of the bus differential protection is stored in the management unit of the main engine, which is convenient for operation Personnel can check at any time through the man-machine interface of the host. The operation information of the bus differential protection is the binary input quantity, digital quantity, and the communication working condition information between the master unit and the slave unit received by the master unit.

3. Carry out intelligent transformation of traditional substations. As shown in Figure 2, when the primary equipment of the interval to be transformed is powered off, the interval merging unit MU and the intelligent terminal are respectively electrically connected to the primary equipment of the substation in this interval through cables for Collect the required current and voltage alternating current and binary input, then connect the merging unit MU and the intelligent terminal to the host through optical fiber, put in a device, and the merging unit MU and the intelligent terminal will collect the digital quantity of the current and voltage alternating current , The binary input is sent to the host. During the reformation of each interval to connect the merging unit and the intelligent terminal, the master still receives the binary input of the transformed interval and the digital quantity of the exchange volume collected at 80 points per cycle through the slave, and sends it to the merging unit and the intelligent terminal. The digital quantity and binary input quantity of the main engine are not processed to ensure that the bus differential protection is put into operation during the transformation.

4. In the intelligent transformation of traditional substations, for the intervals that have completed the intelligent transformation, the merging unit and the intelligent terminal are connected to the host through optical fiber, and by modifying the communication parameter settings of the host, the collected interval input and exchange volume are controlled by the substation. On-board transmission is switched to merging unit and intelligent terminal transmission. The intelligent terminal of the transformed interval sends the input data in real time, and the merging unit samples the exchange amount of the interval at 80 points per cycle and sends the analog-to-digital conversion to the host to realize the switching of the collected information of the transformed interval. Modify the communication parameters of the host, and modify the receiving parameters of the transformed interval from the network communication MAC address, APPID (application identification in the IEC61850 protocol) and application identification of the sub-machine to the MAC address, APPID, and application identification of the merging unit and the intelligent terminal.

5. All bays are connected to the merging units and intelligent terminals, as shown in Figure 3, the main unit is connected to the merging units and intelligent terminals in all bays, and all slave machines are removed to complete the transformation of the intelligent substation.

As an important device in the transformation process of digital bus differential protection, the sub-machine collects binary input quantities at multiple intervals separately, and simultaneously performs AC volume sampling, converts the sampled AC volume into digital quantities, and then converts the binary input quantities and digital quantities into digital quantities. data transfer to the host.

The host computer is the bus differential protection device that is finally operated in the substation for a long time. After the traditional substation is intelligently transformed, the host computer receives the digital quantities of the current and voltage alternating currents sent by each interval merging unit, and the digital quantities of the primary equipment sent by the intelligent terminal. Position signal (binary input), after calculation, judge the running status of the bus. Through the man-machine interface of the bus differential protection device, the operator can check the operating conditions of the busbar at any time. When the busbar runs abnormally, the alarm light of the main engine will give an alarm, and the man-machine interface will give an alarm message, and send the alarm information to the main control room through the network established in the station. The automatic monitoring system sends real-time information about the abnormal operation of the busbar, the host sends out a protection action signal, and a switch trip is realized through the output relay of the intelligent terminal. The operation information of bus differential protection is stored on the host computer. In the process of intelligent transformation, the master receives the binary input and digital quantities sent by the slave to protect the busbar. When the master sends a protection action signal, the switch is tripped once through the output relay of the slave.

The intelligent terminal is an intelligent component, which is connected with the primary equipment of the substation by cable, and connected with the secondary equipment such as protection and measurement and control by optical fiber. The smart terminal collects the binary input of the primary device and transmits the binary input to the host; receives the output output of the host to control the action of the primary device. The primary equipment of the substation is the equipment for power transmission and distribution of the substation, including circuit breakers, isolation switches, main transformers, etc.

Merging unit Physical unit for time-dependent combining of current and voltage quantity data from secondary converters. As an interface device for electronic current and voltage transformers, the merging unit combines and synchronizes the current and voltage quantities, and transmits the processed digital signals to the host. The merging unit can be a component of the electronic current and voltage transformer, or a discrete unit.

As shown in Figure 5, the sub-machine is equipped with an AC sampling circuit (AC sampling board), an analog-to-digital AD conversion circuit, an input circuit (input board), an output circuit (exit board), and an analog sampling SV communication interface (SV Communication interface board), GOOSE communication interface for general object-oriented substation events (GOOSE communication interface board), optical fiber interface, power supply. On the GOOSE communication interface board of the sub-machine, the receiving optical port and the sending optical port are set in pairs. Each circuit and interface adopts 1000M high-speed low-voltage differential signal transmission LVDS (LowVoltageDifferentialSignaling) bus. Each circuit and interface of the sub-machine is reasonably divided into boards, and the calculation amount is reasonably distributed to each board, making full use of the advantages of distributed computing to achieve high performance. The sub-machine can realize 12-channel interval AC sampling and binary input and output transmission. Adopt the precision clock synchronization protocol standard IEEE1588 of the network measurement and control system to synchronize the time, and cooperate with the host to complete the synchronization of the AC sampling and the time synchronization of the bus differential protection device without relying on the external clock.

The sub-machine completes the following tasks:

1. Complete multi-interval AC sampling and synchronization, convert the AC sampling value to AD conversion and send it to the host through the directly connected optical fiber with the substation communication network and system protocol IEC61850-9-2 protocol message.

2. Collect multi-interval binary input data, and send the binary input data to the host computer as GOOSE protocol messages through direct-connected optical fibers.

3. Through the direct connection to the optical fiber receiving host, the output is output at the interval of the GOOSE protocol message, and then tripped through the relay outlet.

The working method of the sub-machine is:

1. AC acquisition, the AC sampling board of the sub-machine collects the AC quantity (AC sampling value) of multi-interval current and voltage, and the AD conversion circuit converts the AC sampling value to the digital quantity obtained after AD conversion (AC sampling data), and sends it to the SV Communication interface board, the SV communication interface board combines the received AC sampling data of each interval, and then packs the merged AC sampling data of each interval into a frame according to the IEC61850-9-2 protocol, and transmits the data through the SV communication interface board. The module converts it into an optical signal, and sends the message containing the AC sampling value information to the host through the ST model optical fiber interface and the connected optical fiber cable.

2. Collect binary input and output trips. The input board of the sub-machine collects multi-interval input signals and sends them to the GOOSE communication interface board. The GOOSE communication interface board converts the binary input signals into digital information. According to the GOOSE function of the sub-machine Module setting selects the binary input data required by the host, packs the selected binary input data according to the GOOSE message format stipulated in the IEC61850 standard, converts the optical signal into an optical signal through the optical module on the GOOSE communication interface board, and passes through the ST model optical fiber interface and its connection The optical fiber connection sends the message containing binary data to the host.

The GOOSE communication interface board of the slave machine simultaneously receives the GOOSE trip message sent by the host and analyzes the message in accordance with the format specified in the IEC61850 standard to obtain the current action command issued by the host. When the GOOSE message corresponds to an interval set trip exit command , the GOOSE communication interface board sends the export command to the export board to control the export trip of the corresponding export relay.

3. IEEE1588 synchronous time synchronization, according to the different roles in the synchronization process, the devices on the network can be divided into two types, master clock and slave clock. The clock that provides a synchronous clock source is called the master clock, and the clock that is synchronized with it is called the slave clock. Therefore, the master clock and the slave clock are relative, and any network clock can act as the master clock and the slave clock. As shown in Figure 4, in the first stage, when only the master and the slave are connected, the master is used as the master clock, and the slave is used as the slave clock. The host and the slave are directly connected in a point-to-point manner without relying on an external synchronous clock. And network switches perform internal synchronization, with high communication reliability and high synchronization performance. As the transformation progresses, the host is connected to the switch network, the active and standby clock sources are used as the master clock, and the host, intelligent terminal and merging unit are all used as slave clocks to receive the synchronization timing messages of the master clock to achieve synchronization. As a slave clock, the slave machine can use the master clock as the master clock to perform synchronous time calibration, and can also receive network synchronization time calibration messages together with the host machine, intelligent terminal, and merging unit as the slave clock through the switch network established in the access station.

In this embodiment, the 330kV traditional substation is transformed into an intelligent substation. The number of bays is 16. The first sub-machine is connected to 12 bays, and the second sub-machine is connected to 4 bays. BP-2C-D busbar protection device, the merging unit adopts BP-2C-D busbar protection sub-machine of Changyuan Shenrui Jibao Automation Co., Ltd., and the intelligent terminal adopts NSR351D of Guodian Nari Technology Co., Ltd., which is divided into three stages :

1. In the first stage, the host and sub-units are connected and put into operation, so as to reduce the power outage time of equipment during the intelligent transformation process and ensure that the busbar equipment is in a protected state. There are two specific project implementation plans:

For the case of dual traditional bus differential protection configuration, one set of traditional bus differential protection configuration is always put into operation, and the other set of traditional bus differential protection configuration is taken out of operation, and the AC volume, The terminals of the binary input and output cables are connected to the sub-unit in sequence, and the main unit and the sub-unit are connected through optical fibers. After the wiring changes of all access sub-units are completed, a connection is established with the main unit. By checking the display of the main unit, determine the data collected by the main unit. The AC volume and binary input volume are consistent with those collected by a set of traditional bus differential protection on site, and then test the bus differential protection logic and output circuit through the tester. After confirming that there is no problem with the connection, connect the digital bus differential protection The protection sub-machine is put into operation.

For the case of single-duty traditional bus differential protection configuration, if the outdoor circuit breaker and the secondary side of the transformer have spare contacts for the AC volume and binary inputs and outputs that need to be connected to the bus differential protection, connect the spare contacts through cables The sub-machine can connect the AC quantity of each interval circuit, the terminal of the binary input and output cable connection to the sub-machine according to the order designed in the design drawing, and connect the main machine and the sub-machine through the existing traditional bus differential protection. Optical fiber connection, after the wiring changes of all access sub-units are completed, establish a connection with the main unit. By checking the main unit’s display, make sure that the AC volume collected by the main unit, the input and output quantities are consistent with the site, and then use the tester to check the protection logic of the bus differential and Open the circuit for testing, and after confirming that there is no problem with the connection, put the digital bus differential protection main unit and the digital bus differential protection sub-machine into operation.

If there is no spare contact for the AC volume, binary input and output required for the configuration of the traditional bus differential protection, in order to reduce the power outage time of the equipment, it is necessary to withdraw from the traditional bus protection, and replace the existing traditional bus protection as soon as possible. The terminals connected to the AC volume and binary input and output cables of each interval circuit are sequentially connected to the sub-unit, and the main unit and the sub-unit are connected through optical fibers. After the wiring changes of all access sub-units are completed, the wiring between the main unit and the sub-unit is completed. Transformation and testing, put into operation immediately after the test is normal, by checking the display of the host, confirm that the AC volume collected by the host, input and output are consistent with the site, and test the bus differential protection logic and output loop through the tester to confirm the connection After there is no problem, put the digital bus differential protection host and the digital bus differential protection sub-machine into operation.

Considering that the bus differential protection device is a protection device for the bus of the substation, it is very important for the safe operation of the bus. In addition to improving the protection and debugging schemes during the joint commissioning process in the early stage of the transformation, the protection logic of the bus differential protection device and the communication between the master and the slave In addition to verifying and backing up the communication configuration files, it is also necessary to carry out experiments with the host and slave with a circuit breaker after the wiring is completed, so as to ensure the correctness and test integrity of the wiring of the host and slave in operation.

After the completion of the first stage, the wiring of the digital bus differential protection host and the digital bus differential protection sub-machine is shown in Figure 1.

2. The second stage is the power outage reconstruction interval, which is connected to the digital bus differential protection host.

Digital transformation is carried out in conjunction with power outage reconstruction intervals. The transformed interval has a power outage. Since the interval after digital transformation has no cable terminals that can be connected to the traditional bus differential protection device, the traditional bus differential protection device cannot collect information about the transformed interval. Traditional The bus differential protection device will be out of operation. The second stage is the key step of intelligent transformation of bus differential protection. The transformation process mainly includes the following steps:

(1) After the power failure of the primary equipment in the transformed bay, carry out bay-related protection and intelligent transformation of loop wiring, remove the wiring of the bay where the sub-machine has been connected, and connect the bay merging unit MU and the intelligent terminal to the substation of the bay through cables The equipment is electrically connected, the merging unit MU and the intelligent terminal are connected to the host through optical fiber, and the configuration file of the host is replaced.

(2) Debug the bus differential protection device after the transformation, and verify the correctness of the bus differential protection logic, binary input and output, interface control file icd, font format CID, academic citation database SCD file and related virtual terminal wiring.

(3) Invest in the transformation of primary equipment at intervals, observe the correctness and synchronization of AC sampling in each interval of bus differential protection, observe the correctness of differential current and switch-in, if the bus differential protection operates normally, it can be put into bus differential protection.

Figure 2 shows the host connection of the digital bus differential protection in the second stage of transformation.

3. The third stage is that all the transformed bays are connected to the digital bus differential protection host.

After all the intervals for power outage reconstruction are connected to the main unit, the sub-units can be completely removed, and the transformation of the bus differential protection of the intelligent substation is completed. Figure 3 shows the host connection of digital bus differential protection after transformation.

The transformation of bus differential protection adopts the mode of main unit + slave unit. After the work of connecting the main unit is completed, it needs to be tested before modifying the communication parameter settings of the main unit and putting into digital bus differential protection. The test method is as follows:

(1) Synchronous test of sub-machine and interval merging unit

Since the synchronization of AC sampling has a great influence on the calculation of the differential current of the bus differential protection, it is necessary to test the synchronization of the slave unit and the merging unit. In order to ensure the synchronization of AC volume sampling, the master in this embodiment adopts the interpolation synchronization method, and the synchronization does not depend on the external synchronous clock. The merging unit and the slave machine need to send digital quantities containing communication volume information of 80 points per cycle to the host at equal intervals to ensure The channel delay is exactly the same as the actual delay.

As shown in Figure 6, the principle of the interpolation synchronization method: when the bus differential protection receives each sampling value of each channel data of the merging unit and the slave machine, record the corresponding time T11, T12, T13 and T21, T22, T23, and At each resampling time point T when entering the interrupt program, the data of each channel will have sampling values before and after it. According to the value and time difference between the previous and the previous points and this time point, a "synchronous sampling value" can be obtained by using the Lagrangian interpolation algorithm. ", the data "synchronous sampling value" of all channels is at this reference time. The reference time T is shifted backward by a fixed interval, and the calculation is carried out continuously, so that continuous "synchronous sampling values" are obtained.

(2) Bus differential protection configuration test during transformation

The bus differential protection configuration is a necessary file for bus differential protection communication. The file is generated through the system configuration file SCD of the whole station, including the MAC address, APPID, GoID, GOOSE tripping information of the bus differential protection sending GOOSE messages and the communication required for the bus differential protection. The merging unit, intelligent terminal, MAC address, APPID, GoID, svID information of the master differential and slave units, and the file of the sending data information. When the master differential protection is started, the configuration file needs to be loaded, and the parameters in the Send parameters and determine whether the received message is correct and obtain the information required by the device from the received message.

Due to the large number of transformation intervals in this embodiment, the transformation time is tight, and the transformation process is relatively complicated, the bus differential protection configuration has a great influence on the smooth progress of the transformation process. Therefore, in this embodiment, in the process of bus differential protection configuration test (joint commissioning) during the transformation process, the configuration test of bus differential protection is carried out for each stage of the transformation, and the configuration files are saved and backed up at the same time.

The configuration test is to use an analog tester to simulate the intelligent terminal, the merging unit, and the sub-unit or to connect the host with the intelligent terminal, the merging unit, and the sub-unit through optical fibers before the transformation, and download the configuration file to the intelligent terminal, merge unit, sub-machine, check whether the communication between the intelligent terminal, the merging unit, the sub-machine and the main unit is normal, simulate adding binary input and communication volume to the main unit, and check whether the main unit can receive the message correctly. After the alarm and action, it will trip The information and warning information are sent out correctly. The configuration file here is not unique, but with the progress of the transformation, there is a situation where the information collected by the host is switched from the slave to the smart terminal and the merging unit. Each switch of the host corresponds to a configuration file, the slave, smart terminal, Merge unit configuration files are unique.

The special test in the process of joint commissioning ensures the correctness and consistency of the configuration of each file during the transformation process, and at the same time greatly saves the time for configuring and debugging the final operation files of the bus differential protection device during the transformation process, ensuring that the transformation work of the bus differential protection It was carried out smoothly within the planned time and put into operation on time.

The bus differential protection device does not rely on an external time synchronization system to realize its protection function. In this embodiment, the bus differential protection sampling synchronization method adopts an interpolation synchronization method. Since the sampling synchronization has a great influence on the performance of the digital bus differential protection, a special test is carried out on the synchronization of the sub-machine and each merging unit during joint debugging.

The special test method is: use the transformer calibrator to test the sampling delay time of the merging unit and the slave unit. Connect the analog AC output from the standard source to the AC sampling input of the transformer calibrator, connect the same channel of AC sampling to the data acquisition unit DAU merging unit or sub-machine, and connect the merging unit and sub-machine digital sampling output optical port at the same time Connect to the optical port of the calibrator. Connect the synchronous signal of the substation to the synchronous signal input of the transformer calibrator, or use the synchronous signal of the transformer calibrator to connect the synchronous signal output of the transformer calibrator to the merging unit. According to the angular difference and ratio difference output by the transformer calibrator, it can test whether the output delay of the merging unit and the sub-machine is accurate, and determine whether the sampling waveform is qualified. The system synchronization performance of the sub-machine and the merging unit is verified and tested by connecting the current in series and the voltage in parallel. Since the traditional transformer is used in this embodiment, an analog quantity tester can be used as a standard source.

The method of the present invention is suitable for intelligent transformation of traditional substations with a voltage level of 1000kV and below, including single busbar, single busbar section, double busbar, double busbar single section, double busbar double section (realized in a set of devices) And various main wiring methods including 3/2 wiring, the main wiring changes can be completed through configuration. The maximum supported main wiring scale is 36 branches (lines, components and tie switches). The method of the invention adopts a unified sub-machine and system, realizes the standardization and modularization of the sub-machine, the configuration of the system, and facilitates configuration and expansion. The sub-machine is based on gigabit low-voltage differential signal technology interface LVDS bus architecture and special transmission protocol processing, realizes data classification processing, and realizes large-capacity data interaction and low power consumption of bus protection devices. LVDS timing bus, the synchronization accuracy of each CPU board of the sub-machine can reach 0.1us. Applicable to interpolation synchronization and multiple clock synchronization methods (second pulse, B code, IEEE1588).

The transformation process of the method of the present invention does not affect the protection operation mode and load distribution of the whole substation, and is applicable to various main wiring modes; the power outage time of the primary equipment during the transformation is reduced, and the transformed primary equipment only needs to be powered off once, and the bus differential The protection exit time is short, the grid operation reliability is high, the construction difficulty is reduced, the work efficiency is improved, the investment is small, and only the sub-machine screen cabinets need to be added, and the sub-machine screen cabinets can be used repeatedly.

Claims (10)

1. A method for transforming an intelligent substation, comprising the following steps: 1. Information collection, transmission and switching. The transformed traditional substation is equipped with a digital bus differential protection host, and each digital bus differential protection sub-machine is connected to 1-12 bays, and the secondary cables of the traditional substation bus differential protection for each bay are connected. Transfer and connect to the digital bus differential protection sub-machine, the digital bus differential protection sub-machine receives the binary input of the connected interval, according to 80 points per cycle, samples the alternating current and voltage of the connected interval, and converts the alternating current It is a digital quantity, and the binary input quantity and digital quantity are transmitted to the digital bus differential protection host through optical fiber; 2. After receiving the binary input quantity and digital quantity sent by the digital busbar differential protection sub-machine, the digital bus differential protection master judges the operation mode of the bus according to the binary input quantity of each interval, and processes the digital quantity according to the bus protection criterion. Realize the real-time protection of the busbar; 3. For the power failure of the primary equipment in the interval, the interval merging unit and the intelligent terminal are electrically connected to the primary equipment of the substation in the interval through cables, and then the merging unit and the intelligent terminal are connected to the digital bus difference protection host through optical fiber, and put into the primary equipment; 4. For the bays that have completed the intelligent transformation, modify the communication parameter settings of the digital bus differential protection host, so that the collected bay input and exchange volumes are switched from the digital bus differential protection sub-machine to the merging unit and intelligent terminal. Realize the switching of collecting information at the transformation interval; 5. The main unit of digital bus differential protection is connected to the merging units and intelligent terminals of all intervals, and all sub-units are removed to complete the transformation of the intelligent substation. 2. The transformation method of an intelligent substation according to claim 1, characterized in that: in said step 1, the digital bus differential protection sub-machine receives the opening information sent by the digital bus differential protection host, and the digital bus differential protection host sends out protection The action signal is used to realize a switch trip through the output relay of the digital bus differential protection sub-machine. 3. The transformation method of an intelligent substation according to claim 2, characterized in that: the digital bus differential protection sub-machine receives the GOOSE tripping message sent by the digital bus differential protection host and sends the message according to the format specified in the IEC61850 standard Analyze and obtain the action command currently issued by the digital bus differential protection host. When the GOOSE message corresponds to an interval set trip exit command, the exit command is sent to control the corresponding exit relay exit trip. 4. The transformation method of an intelligent substation according to claim 1, characterized in that: said step 2 digital bus differential protection host computer sends the bus differential protection operation information to the automatic monitoring system located in the main control room to realize the operation of substation operators Remote monitoring of bus differential protection; the digital bus differential protection host stores bus differential protection operation information; the bus differential protection operation information is the binary input quantity, digital quantity, and information between the host and the sub-unit received by the host from the sub-machine Communication status information. 5. The transformation method of the intelligent substation according to claim 1, characterized in that: after the step 3 is put into the primary equipment, the merging unit and the intelligent terminal will collect the digital quantity and binary input quantity of the AC quantity of the current and the voltage It is sent to the digital bus differential protection host, and during the transformation of each interval to connect the merging unit and the intelligent terminal, the digital bus differential protection host still receives the binary input of the transformed interval through the digital bus differential protection sub-machine, according to 80 points per cycle The digital quantity of the exchange volume collected does not process the digital quantity and binary input quantity sent to the host computer from the merging unit and the intelligent terminal. 6. The transformation method of intelligent substation according to claim 1, characterized in that: before said step 4 modifies the communication parameter setting of the digital bus differential protection host, test is carried out, and the test method is: Test the synchronization between the digital bus differential protection sub-machine and the merging unit. The merging unit and the digital bus differential protection sub-machine send the digital quantity of AC volume collected at 80 points per cycle to the digital bus differential protection host at equal intervals. The digital bus differential protection The protection host adopts interpolation synchronization method for processing; For the bus differential protection configuration test, use an analog tester to simulate the intelligent terminal, merging unit, and digital bus differential protection sub-machine or simulate the site with the digital bus differential protection host and the intelligent terminal, merging unit, and digital bus differential protection sub-machine before transformation Connect through optical fiber, and download the configuration file to the intelligent terminal, merging unit, and digital bus differential protection sub-machine, and check whether the communication between the intelligent terminal, merging unit, digital bus differential protection sub-machine and digital bus differential protection host is normal, Simulate adding binary input and AC volumes to the digital bus differential protection host to check whether the digital bus differential protection host can receive the message correctly, and send out the trip information and alarm information correctly after the alarm and action. 7. The transformation method of an intelligent substation according to claim 1, characterized in that: said step 4 completes the transformation of the interval intelligent terminal to send the binary input in real time, and the merging unit performs current and voltage on the interval according to 80 points per cycle. The AC volume sampling and analog-to-digital conversion are sent to the digital bus differential protection host. 8. The transformation method of an intelligent substation according to claim 1, characterized in that: the digital bus differential protection sub-machine collects the alternating current and voltage of multiple intervals, and the alternating current sampling data obtained after analog-to-digital conversion converts the alternating current The sampling data are merged together, and the AC sampling data at different intervals are time-synchronized through the difference sampling algorithm, and then the merged and synchronized AC sampling data at each interval are packaged into frames according to the IEC61850-9-2 protocol, converted into optical signals, and passed The optical fiber connection sends the message containing the information of the AC sampling value to the digital bus differential protection host. 9. The transformation method of intelligent substation according to claim 1, characterized in that: said digitized bus differential protection sub-machine collects multi-interval input signals, converts them into digital information, and converts them according to the GOOSE message format stipulated in the IEC61850 standard After the selected binary input is packaged, it is converted into an optical signal, and the message containing the binary input data is sent to the digital bus differential protection host through the optical fiber connection. 10. The transformation method of intelligent substation according to claim 1, characterized in that: said step 1, for dual traditional bus differential protection configuration, one set of traditional bus differential protection configuration is always put into operation, and another set of traditional bus differential protection configuration is always put into operation. The bus differential protection configuration is out of operation, and the terminals of the AC volume, binary input and binary output cable wiring of each interval circuit before the withdrawn traditional bus differential protection configuration are sequentially connected to the digital bus differential protection sub-machine; For the single-duty traditional bus differential protection configuration outdoor circuit breaker, the secondary side of the transformer has the AC volume required for the bus differential protection, the spare contacts of the input and output, and connect the spare contacts to the digital bus differential protection through the cable Sub-machine, do not withdraw from the existing traditional bus differential protection; The AC volume, binary input and output required for the configuration of traditional bus differential protection. If there is no spare contact, exit the traditional bus protection, and the AC volume, binary input and output of each interval circuit connected before the exiting traditional bus differential protection device Connect the terminals of the measurement cable to the sub-machine in sequence.