The control of the electrical parts of Texas Electric/#3 and #4300MW units originally used the form of traditional relays and special devices, but with the continuous improvement of the level of automation technology and reliability of DCS, as well as the improvement of automation requirements of the electrical itself, the electrical part will be The integration of control into the DCS control of the entire unit has become feasible and necessary.

This time, the ECS system was upgraded and the hardware and software system used the DCS product XDPS-400 from Shanghai Xinhua Control Engineering Co., Ltd., and together with the DCS transformation of the thermal system, the integration of hardware and software was realized; the scope involved included the development of New Zealand. System (including excitation system), high-voltage plant power system, low-voltage plant power system, public system, etc.; completed functions include automatic quasi-period synchronization, rapid switching of plant power, excitation system adjustment, automatic program control switching of plant power, etc. .

Now briefly introduce the control functions that can be completed by the system after transformation.

First, hair change group system (including excitation system).

The system includes generators, main transformers, high plant transformers, two 500kV switches, automatic quasi-synchronization, manual quasi-synchronization, automatic excitation regulators, spare-induction voltage regulators, Q7 switches, Q6 switches, and QE switches.

The generator set control has automatic program control and manual/hatch control. Before the whole unit starts, call out the primary system diagram of #1 unit electrical once. After the start-up procedure is completed, the plant power will be switched to the high-voltage plant work change. Before the shutdown of the complete unit program, the power supply of the plant is switched to start/standby and the complete unit program is shut down.

Before the unit starts, the CRT/mouse selection window can be used to select the mode using automatic program control or manual sequence control. The generator booster juxtaposition can be performed in one of the following four ways.

. Automatic regulator step-up, automatic quasi-synchronization (automatic program control)

. Automatic regulator step-up, manual synchronizing parallel (manual/history control)

. Manually-boosted boost, automatically synchronizing the same period (manual sequential control)

. Manually-boosted boost, manual quasi-periodical juxtaposition (manual sequential control)

After the generators are paralleled and closed, the circuit breaker icon in the ECS is red and flat, and the device and the switch closing circuit automatically return during the same period. After the ECS accepts the manual or automatic synchronization command, a signal is displayed on the CRT. After the parallel closing conditions are met and confirmed by the operator, the circuit breaker can be manually or automatically closed. Otherwise, the circuit breaker closing circuit is closed.

The circuit breaker icon in the ECS flashes green when the generator-transformer protection action trips. After the manual reset, a green flat light is emitted.

Second, high-voltage plant power system This feature includes the operation of 6301 switch, 6302 switch, 6310 switch, 6320 switch and other equipment.

High-voltage factory power supply switching is divided into two modes, automatic and manual, and a “manual-automatic” switching window is provided on the CRT screen.

When the ECS system automatically switches the high-voltage plant power supply from the working power supply to the standby power supply, or switches from the standby power supply to the working power supply, both the pre-closed and the post-breaking methods are used, and the current is used as the switch to verify the combination, so as to ensure the plant The bus does not lose power.

In addition, when the factory power supply is automatically switched, the factory breaker circuit of the ECS in the closing and closing circuit and the quick-switching synchronous verification relay are matched to each other, and software and hardware are simultaneously used to ensure that non-synchronous closing occurs.

Third, the low-voltage plant power system This function includes the operation of the two related switches of low plant change (single unit), low standby and other equipment.

Low-voltage plant power supply switching is also provided with both automatic and manual modes. The CRT provides a "manual-automatic" switching operation window.

When the low-voltage factory power supply is normally switched from the working power supply to the standby power supply, or when the standby power supply is normally switched to the operating power supply, the first-combined cut-off operation is also adopted, and the current is used as a switch for verification.

Fourth, the electrical picture electrical picture adopts the cascading way, from each system operation picture, can switch to the operation picture of other systems according to need again.

The device's snap-in status is differentiated by different colors on the screen. Red indicates the closing status and green indicates the disconnected status. When the circuit breaker accident trips, the circuit breaker display glows green until manual reset. The main switch quantity has accident recalls, the trend chart of the main analog quantity, the stator and rotor current and voltage can all be directly viewed on the CRT. There are real-time values ​​displayed on the nodes where the voltage, current, and power transmitters are installed.

DCS provides the following electrical screens:

, utility power system diagram (public system)

. Generator-transformer group system diagram, generator excitation system diagram. Plant power system diagram. 6kV system diagram. #3 (#4) machine 380V work section. 380V security section system diagram, DC system diagram. Alarm light word picture 5. Sequence control function For each subgroup item and related equipment, their status, start permission conditions, operation sequence and operation mode are displayed on the CRT. In the manual and sequential control modes, ECS can provide operational guidance for operators according to the operating procedures. These operation instructions are graphically displayed on the CRT, that is, in accordance with the sequence, display the next step of the program to be executed, and change the color of the corresponding device on the CRT according to the feedback signal of the change of the device state.

The operator is guided by the graphical operation on the CRT. If the automatic execution of the interrupted program is performed, the program will automatically return to the previous step until the operator confirms that the program can be executed automatically.

Each step in the control program is confirmed by the feedback signal from the device, and each step monitors the scheduled execution time. If the program fails to complete within the agreed time, an alarm signal is issued and the program is prohibited from proceeding. If the fault is removed, the program will continue automatically after the operator restarts.

During automatic program control, any malfunction or interruption of the operator's signal will interrupt the ongoing program and automatically return to a safe state so that a program interruption fault or operator command will be displayed on the CRT. When the fault is removed, the program control can continue to start after confirming the error.

Program control is performed in the order of logical order, with checks at each step. In normal operation, the program goes to the end.

At the same time, the operator can operate each controlled object through the CRT/mouse.

VI. Operational Authority The operating authority of the ECS system is divided into read-only, control, engineering and system management.

. Operators with read-only privileges only allow observation of the current operating state.

. Control authority operators allow control operations and so on.

. The engineering processing authority operator has the right to observe and operate in addition to the user management.

. System management authority operators allow all rights including user management.

Once you start the operation of any device that will enter the device regardless of the above four levels of operator, there are confirmation windows besides the operation window. Only when both have input, can the operation take effect.

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