- Remote monitoring
Remote monitoring is to dispatch the power station through the communication network in the dispatch center. The power dispatch center monitors and controls the entire power station system from a global perspective. Monitoring and safety analysis, state estimation, load forecasting, remote control, etc., to ensure the safe and stable operation of the power grid, improve power quality, ensure the economical operation of the power grid and participate in enterprise management. This project connects the web server of the local monitoring room through the Internet To realize the communication with the dispatch center, the connection between the Hudu Center and the photovoltaic power station adopts the motion protocol of the international standard IEC60870-5-144 based on TCP/IP for the electric power motion system.
- Introduction to the 104 Statute
The IEC60870-5-144 statute is referred to as the 104 statute. It is a data communication standard for dispatching automation systems and substation automation systems formulated by the International Electrotechnical Commission Power System Control and Communication Technology Committee (IECTC57) according to the requirements of formal development. The telecontrol equipment and system for encoding and transmitting bit data are used to monitor and control the geographical wide-area process. The purpose of formulating the motion supporting standard is to achieve interoperability between compatible telecontrol equipment. This supporting standard uses the international standard 1EC60870 -5 series of documents, which stipulate the combination of the application layer of 1EC60870-5-141 and the transmission function provided by TCPIP, because the limitation of the sampling system of the integrated automation station is completely negligible, and its transmission delay depends on the network load. Basically it is calculated in a few milliseconds.
The 104 statute has changed the traditional real-time data bottle transmission using the Shenkou communication mechanism in the power grid dispatching system. Instead, it uses the Internet technology for dispatching. Compared with the previous sports technology, it is more eloquent, simple and economical.
- Realization of data communication
The core of the software design of the local monitoring room and dispatch center is to solve the realization of the communication protocol. This part also uses C# language and VS2010 development tools, adopts modular structure design, and is realized by four parts:
① Establish a connection with the database: the main function is to establish a connection with the data motorcycle through ADO.NET
② Establish a connection between the dispatching center and the photovoltaic power station: According to the 104 network transmission protocol, the connection between the dispatching center and the power station is realized.
③Protocol interpretation: mainly interpret the received message according to the content of the 104 protocol, and process the data to make it into the cooked data that can be used by each thread module.
④Interface display: Real-time display of the real-time communication and telemetry information of the photovoltaic power station on the screen in the form of a web page, as well as the operation status of each part of the power station.
- Connection between dispatch center and power station
The outside is the focus of remote communication. According to the relevant regulations of the 104 network transmission standard, the establishment of a TCP connection between the dispatch center and the power station is called station initialization. The release of this connection can be proposed by the control station or the controlled station. In this project The control station is the dispatch center equivalent to the client (connector), and the controlled station is the photovoltaic grid-connected power station equivalent to the server (listener). There are two ways to establish the connection between them:
①A connection is established between a pair of control stations and the control station in the controlled station;
②Two equal control stations, fixed by one of the stations to establish a connection
To close an established connection, firstly, the control station sends an active close request to TCP, and then the controlled station sends a passive close request to TCP to establish a new connection. First, the control master station sends an active open request to TCP, and then the controlled station sends an active open request to TCP. Send a passive open request to TCP, and finally display the option to actively close the connection by the controlled station.
When the display control station is initialized, a connection is established with each controlled station in turn. Starting from slave station 1, the control station sends an active open request to the TCP. If the TCP of the controlled station has a listening state (the state is not shown in the figure), the connection is established. The same process is repeated for other controlled stations.
Displays the controlling station repeatedly trying to establish a connection with the controlled station. The connection is not successful until the controlled station completes the local initialization, sends a passive open request to TCP, and obtains the listening state (the state is not shown in the figure).
The display control station sends an active open request to TCP to establish a connection. Then send a Reset Process command to the controlled station, the controlled station returns confirmation and sends out an active close request to TCP, and the control station sends a passive close request to TCP and the connection is released. Then the control station sends an active open request to the TCP loop to try to connect to the controlled station. When the controlled slave station completes initialization and becomes available again, the controlled station returns CLT=SYN.ACK, when the control confirms CIT-SYN.ACK, the connection is established.
- Example message parsing
According to the analysis of the 104 protocol, this book parses the message with a communication program in this project.
The first step: first handshake (U frame)
Send → Activate Transmission Start: 68 (Initiator) 04 (Length) 07 (Control Field) 00 00 00
Receive → Confirm Activation Transmission Start: 68 (Initiator) 04 (Length) oB (Control City) 000000
Step 2: Total Summons ((1 frame)
Summon RC (Remote Control), RS (Remote Signal) (variable length 1 frame) and send a general call regularly after initialization. The interval time of each general call is generally set to call once every 10 minutes. Different master station systems have different settings.
Send → general call: 68 (starter) OE (length) 00 00 (send sequence number) 0000 (receive sequence number) 64 (type indicator) 01 (variable structure qualifier) 06 00 (transmission reason) 01 00 (public address is RTU address) 0000 00 (message body address) 14 (used to distinguish general call and group call)
Receive → S frame: 68 04 01 00 02 00
It should be noted that when recording the received long frames, both parties can send them according to the frequency. For example, if they receive 8 frames and 1 frame, they can reply to 1 S frame.
Receive → general call confirmation (mirror of the sent frame, only the reason for the transmission is different):
68 (starter) OE (length) 0000 (send sequence number) 00 00 (receive sequence number) 64 (type indicator) 01 (variable structure qualifier) 07 00 (transmission reason) 01 00 (public address is RTU address) 00 00 00 (message body address) 14 (used to distinguish general call and group call)
Send → S frame: 68 0401 00 02 00
Receive → RS frame (take type identifier 1 as an example):
68 (starter) 1A (length) 02 00 (sending serial number) 02 00 (receiving serial number) 01 (type designation, single-point remote signaling) 04 (variable structure qualifier, 4 remote signaling are sent) 14 00 ( Reason for transmission, response to general call) 0100 (public address is RTU address) 03 00 00 (message body address, No. 3 remote signal) 00 (compulsion score)
Send → S frame: 68 04 01 00 04 00
Receive → RS frame (take type identifier 3 as an example):
68 (starter) 1E (length) 04 00 (sending serial number) 02 00 (receiving serial number) 03 (type designation, two-point remote signaling) 05 (variable structure qualifier, 5 remote signaling are sent) 14 00 ( Reason for transmission, response to general call) 01 00 (public address) 0100 00 (message body address, No. 1 remote signal) 02 (remote communication) 06 00 00 (message body address, No. 6 remote signal) 02 (Force letter combined) 0A 00 00 (information body address, No. 10 forced letter) 01 (communication point) OB 00 00 (information body address, No. 11 forced letter) 02 (information body address, No. 11 forced letter) 02 (information body address, No. 11 forced letter) No. 12 remote signaling) 01 (remote signaling)
Send → S frame: 68 04 01 00 06 00
Receive → RC frame (take type ID 9 as an example)
68 (initiator) 13 (length) 06 00 (send sequence number) 02 00 (receive sequence number) 09 (type label, forced measurement with quality description) 82 (variable structure qualifier, 2 consecutive telemetry uploads) 14 00 (transmission reason, response to general call) 0100 (public address) 01 07 00 (message body address, telemetry No. 0 starting from 0x0701) AI 10 (remote state value 10A1) 00 (quality description) 89 15 (telemetry value 1589) 00 (Quality Description)
Send → S frame: 68 04 01 00 08 00
Receive → end general call frame
68 (starter) OE (length) 08 00 (send sequence number) 02 00 (receive sequence number) 64 (type designation) 01 (variable structure qualifier) 0A 00 (transmission reason) 01 00 (public address) 00 00 00 information body address) 14 (to distinguish whether it is a general call or a group call, there is no group call in the revised 2002 statute)
Send → S frame: 68 04 01 00 0A 00
Step 3: Send a synchronization message (by setting the “inter-pair interval” in the parameter table of the photovoltaic power station, the unit is minutes, usually 15min)
Send → time synchronization command
Information Body address) 02 (old second low) 03 (millisecond high) 04 (minute) 05 (hour) 78 (day and week) 09 (month) oC (year)
Receive → time confirmation:
68 (starter) 14 (length) oc 00 (send sequence number) 02 00 (receive sequence number) 67 (type identifier) 01 (variable structure qualifier) 07 00 (transmission reason) 01 00 (public address “00 00 00 ( Message body address)(Millisecond low order).(Millisecond high order)**(minute)05(hour)78(day and week)09(month)oC(year)
Send → S frame: 68 04 01 00 0E 00
Step 4: General Summoning of Electricity (if there is no electricity, this step can be omitted, or it can be transmitted before the time is set, by setting the “full data scan interval” in the parameter table, the unit is minutes, generally 10min call a handover, if There is no need to summon the electricity, and the number of electricity in the parameter must be set to 0)
Send → Summon Electricity:
68 (starter) OE (length) 01 00 (send sequence number) OE 00 (receive sequence number) 65 (type indicator) 01 (variable structure qualifier) 06 00 (transmission reason) 01 00 (public address) 00 00 00 information body address) 45 (quality description)
Receive → Summon Confirmation (mirror of the sent frame, only the reason for the transmission is different)
68 (starter) OE (length) 10 00 (send sequence number) 06 00 (receive sequence number) 65 (type designation) 01 (variable structure qualifier) 07 00 (transmission reason) 01 00 (public address) 00 00 00 information body address) 45 (quality description)
Send → S frame: 68 04 01 00 12 00
Receive→Electricity data
68 (starter) 1A (length) 1200 (send sequence number) 06 00 (receive sequence number) OF (type designation) 02 (variable structure qualifier, there are two electrical quantities sent) 05 00 (transmission reason) 01 00 ( Public address) o1 oc oo (information body address, starting from OXoco1, the 0th electrical degree) 00 00 00 00 (electricity value) 00 (descriptive information) 02 0c 00 (information body address, starting from oxoCo1 on the 1st electrical degree) ) 00 00 00 00 (electricity value) 01 (descriptive information)
Send → S frame: 68 04 01 00 14 00
Receive → end general call frame:
68 (starter) OE (length) 1400 (send sequence number) 0600 (receive sequence number) 65 (type indicator) 01 (variable structure qualifier) 0A 00 (transmission reason) 01 00 (public address) 00 00 00 message body address ) 45 (Quality Description)
Send → S frame: 6804 01 00 1600
Step 5: If the photovoltaic power station has changed data, it will be sent actively, which is equivalent to a remote message, and the type ID is 1 or 3 to receive a message:
68 (starter) OE (length) 16 00 (sending serial number) 06 00 (receiving serial number) 01 (type designation, single-point remote signaling) 01 (variable structure qualifier, there is 1 variable to force the message to be sent) 0300 (transmission reason, indicating emergency) 0100 (public address is RTU address) 03 00 00 message body address, No. 3 remote signal) 00 (return point)
Send → S frame: 68 04 01 00 1800 Receive a letter:
68 (starter) OE (length) 18 00 (sending serial number) 06 00 (receiving serial number) 03 (type designation, double-point remote signaling) 01 (variable structure qualifier, with 1 displacement remote signaling) 03 00 (transmission reason, emergency event) 0100 (public address is RTU address) 06 00 00 message body address, No. 6 remote signaling) 01 (remote signaling)
Send → S frame
68 04 01 00 1A 00
Actively send SOE. Type identification is OX1E or OXIF receive-SOE:
68 (starter) 15 (length) 1A 00 (sending sequence number) 06 00 (receiving sequence number) 1E (type designation, single-point remote signaling) 01 (variable structure qualifier, with 1 SOE) 03 00 (transmission reason, Table emergencies) 01 00 (public address is RTU address) 08 00 00 message body address, No. 8 communication) 00 (communication minutes) AD (old second low) 39 (old second high) 1C (minute) 10 (hour) ) 7A (day and week) OB (month) 05 (year)
Send → S frame: 68 04 01 00 1C00
Receive → SOE
68 (starter) 15 (length) 1C 00 (sending sequence number) 06 00 (receiving sequence number) IF (type designation, double-point remote signaling) 01 (variable structure qualifier, with 1 SOE) 03 00 (transmission reason, Table emergencies) 0100 (public address is RTU address) OA 00 00 (message body address, the 10th remote signal) 01 (remote signal minutes) 2F (old second low order) 40 (old second high order) 1C (minute) 10 ( Hour) 7A (H and week) OB (month) 05 (year)
Step 6: If the master station does not send any message within a certain period of time or the power station does not send any message, both parties can send the U-lock test flight at the quota rate.
Send → U frame: 68 04 43 0000 00
Receive→Reply: 68 04 83 00 0000
Step 7; Remote Control
Send→Remote Preset:
68 (starter) OE (length) 2000 (sending sequence number) 06 00 (receiving sequence number) 2E (type indicator) 01 (variable structure qualifier) 06 00 (transmission reason) 01 00 (public address is RTU address) 05 0B 00 (information body address, control number -охB05-0XB01-4) 02 (control)
Receive→Remote back to school;
68 (starter) OE (length) OE 00 (send sequence number) 06 00 (receive sequence number) 2E (type indicator) 01 (variable structure qualifier) 07 00 (transmission reason) 01 00 (public address is RTU address) 05 0B 00 (information body address, control number=0XB05-0XB01=4) 02 (control combined)
Send → communication execution:
68 (starter) OE (length) 04 00 (sending sequence number) 18 00 (receiving sequence number) 2E (type indicator) 01 (time-varying structure qualifier) 06 00 (transmission reason) 01 00 (public address is RTU address) 05 0B 00 (information body address remote control number – 0XB05-0XB01-1) 02 (control)
Receive → execute confirmation:
68 (starter) OE (length) 12 00 (send sequence number) 08 00 (receive sequence number) 2E (type indicator) 01 (variable structure qualifier) 07 00 (transmission reason) 01 00 (public address is RTU address) 05 0B 00 (information body address, control number=OXB05-0XB01-4) 02 (control combined)
Send→Remote Undo:
68 (starter) OE (length) 04 00 (send sequence number) 18 00 (receive sequence number) 2E (type indicator) 01 (variable structure qualifier) 08 00 (transmission reason) 01 00 (public address is RTU address) 05 0B 00 (information body address, remote control number=0XB05-0XB01=4) 02 (control)
Receive → Cancel confirmation:
68 (starter) OE (length) 1200 (sending sequence number) 0800 (receiving sequence number) 2E (type indicator) 01 (variable structure qualifier) 09 00 (transmission reason) 01 00 (public address is RTU address) 05 0B 00 (Information body address i control number=0XB05-0XB01=4) 02 (control)
Supplementary Instructions
①The length in the message refers to all bytes except the start character and length bytes.
② Note that the “sending sequence number” and “receiving sequence number” in the long frame message have the function of preventing message loss.
③ Commonly used type identification.
Telemetry: 09 – measurement value with quality description, each telemetry value occupies 3 bytes
0A – Measured value with 3-byte time stamp and quality description, each telemetry value occupies 6 bytes
0B – scaled value without time stamp, each traceback value occupies 3 bytes
0C – Scaled value with 3 timestamps, 6 bytes per telemetry
0D – floating point value with quality description, each telemetry value occupies 5 bytes
0E – Floating point value with 3-byte time stamp and crystal description, each telemetry value occupies 8 bytes
15 – Telemetry value without crystal description, each telemetry value occupies 2 bytes
Coercion: 01——Single-point coercion without time stamp, each coercion occupies 1 byte
03 – two-point communication without time stamp, each communication occupies 1 byte
14 – Group single-point remote signaling with state change detection, 8 remote signaling per byte
SOE: 02 – Single point remote signaling with 3-byte short time stamp
04 – Two-point remote signaling with 3-byte short time stamp
1E——Single-point remote signaling with 7-byte time stamp 04 Double-point remote signaling with 7-byte time stamp
KWH: 0F – electric energy without time scale, each electric energy occupies 5 bytes
10 – Electric energy with a short time scale of 3 bytes, each electric energy occupies 8 bytes
25 – Electric energy with 7-byte short time stamp, each electric energy occupies 12 bytes
other:
2E – two point remote control
2F – two-point remote adjustment
64 – Summons Full Data
65 – Summons Full Electricity
67 – Clock Synchronization
④ A list of commonly used transmission reasons.
1 – cycle, cycle
2 – Background Scan
3 – burst
4 – Initialization
5 – Request or be requested
6 – Activate
7 – Activation Confirmation 8 – Stop Activation
9 – Stop Activation Confirmation
0A – end of activation
14 – Answering the general call
- Dispatch center interface display
Enter subrinaliu.oiep.net in the address bar of the IE browser to log in to the user login interface of the PV grid-connected monitoring system, as shown in Figure 5-29. This interface displays the basic information of the monitoring system. After logging in successfully, you can learn more about the operating status and environmental parameters of the photovoltaic grid-connected power station. The login interface is the channel for administrators to enter the system, which shields the users who illegally enter the system. This method ensures the security of the photovoltaic grid-connected monitoring system.
After entering the user name and correct password on the login interface, enter the main monitoring interface of the system, and then select the interface through the left column menu. The current power station operation information interface is shown in Figure 5-30, which displays the current total power generation, cumulative total power generation, online active power and current environmental conditions in real time.
Inverter monitoring interface, it can display the operating parameters of each inverter in real time, including: voltage, current, power, daily power generation, cumulative power generation, cumulative CO2 emission reduction, daily power generation curve; monitoring fault information includes: Grid overvoltage, grid low voltage, inverter overload, inverter short-circuit, DSP fault, communication failure, etc. combiner box monitoring interface, combiner box has 16 inputs, the interface will display the current of each combiner box, if When the current of a certain channel is too low, the box displaying the current value turns into a red alarm, the image is clear, and the alarm is clear and intuitive.
The alarm information query interface displays each uploaded device fault information and alarm information in the format of year, month, day, hour, minute and second, and stores it in the hard disk for historical retrieval.
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