According to the requirements of Ukrainian regulatory documents – СОУ-Н ЕЕ ЯЕК 04.156:2009 і СОУ- Н ЕЕ 04.157:2009 on the load-frequency control in the UPS of Ukraine, the Automatic Load-Frequency Control System (ALFCS) of the IPS of Ukraine, with sufficient static and dynamic accuracy, should keep a load of individual power units and TPP as a whole according to assignment, which are formed by a Master controller of the ALFCS of the IPS of Ukraine (SE «NPC Ukrenergo»).
 
To fully ensure this requirement, each power plant is obliged to implement the Power Plant Control System (PPCS).
 
The power plant's PPCS is a constituent part of ALFC system of the IPS of Ukraine which is intended to link the Master controller of the ALFCS of the IPS of Ukraine with Automatic Load Control System (ALCS) of power units under the centralized load management of power units, which are involved to an Automatic Secondary Load-Frequency Control in the IPS of Ukraine.

 

Functional features of the PPCS are:

• receiving from the MC ALFCS of the IPS of Ukraine an assignment of active-power planned component for the power units participating in an automatic secondary control, and transferring them this assignment by it with ensuring of a follow-up control over the execution;
• receiving of control commands on an unscheduled component of the active-power assignment and transferring them into power unit control systems;
• calculations of reserves for control, proceeding from current value of loads of power units (ranges secondary and a tertiary controls of power units, which participate in automatic control of the IPS of Ukraine);
• automatic realization of daily pre-production;
• receiving assignment on an active-power, for remote control by a master controller of the ALFCS of the IPS of Ukraine, and transferring the registered information concerning electricity supplies, to the SE «NPC Ukrenergo», participation of power units in the normalized primary, secondary and a tertiary load-frequency control in the IPS of Ukraine (monitoring of participation in control);
• exchange of Information with DC of SE «NPC Ukrenergo» and DC of regional PS of the NPC «Ukrenergo»;
• maintaining the market in the provision of system services and ancillary services;
• gathering of technological data/values of production and their archiving;
• formation and processing of the obtained data/values and their delivery on request;
• management of control system and control of power unit/units.

 

The PPCS leads with sufficient static and dynamic accuracy the loads of separate power units and TPPs as a whole in accordance with the assignments formed by the MC of ALFCS of the IPS of Ukraine (NPC «Ukrenergo»), and provides:

• changing the loads of TPP power units under the action of the Master controller of ALFCS of the IPS of Ukraine;
• changing the load of TPP under the action of tertiary frequency control and while changing a planned load of the TPP.

 

 Objective of implementation of the power plant control system:

• improving a reliability of the TPP operation as part of the IPS of Ukraine;
• ensuring a participation of TPPs units in an automatic load-frequency control (through power plant control system connection to a Master ALFCS controller of the IPS of Ukraine) in concordance with requirements of regulatory documents СОУ-Н ЕЕ ЯЕК 04.156:2009 і СОУ-Н ЕЕ 04.157:2009;
• ensuring informational exchange between the MC ALFCS of the IPS of Ukraine and the APCS of TPPs power units by means of the PPCS;
• ensuring provision of auxiliary services by power plant, including with allowance for participation of power units in a tertiary control, with the participation in the balancing market, bilateral contracts market and market of auxiliary services in the IPS of Ukraine;
• implementation of the monitoring system for providing of auxiliary services by TPP (load-frequency control);
• cdata gathering required for controlling remote metering and telesignals providing state and positions of TPP’s switching devices;
• output of telemetric information to the automated workstation (AWS) of the shift supervisor of TPP;
• gathering and transmission of the telemetering information on electricity production and its quality indicators to a Dispatch center of regional PS of the NPC «Ukrenergo», Dispatch center of the SE «NPC Ukrenergo», Control center of generating company, if any, using international standard communication Protocol IEC-870-5-101 (104).
• preservation in an archival database of the telemetering data and information on participation of power units in load-frequency control, including participation in a normalized primary control, in the IPS of Ukraine.

 

Elaboration of software and technical complex of PCS is formed based on the following principles:

• reliable operation within the prescribed period of operation;
• open architecture of building with full compatibility with other systems;
• ensuring a redundancy;
• ensuring a maintenance of common database;
• ensuring a flexibility of system;
• fixing parameters with reference to a precise astronomical time («time stamp»);
• information exchange is carried out using standard international protocols;
• protection against data loss during normal operation or malfunction (saving the whole information transmitted with reference to astronomical time and event log on the operation of the PPCS of TPP);
• protection against unauthorized access;
• possibility of further expanding the system functions by joining new modular systems.

Control and organizational structure is presented in the block diagram

 

From a master controller of the ALFCS of the IPS of Ukraine the power plant control system receives a command signal to change an output of power unit(s), which is registered and immediately transferred to power unit(s) for execution. Then PPCS, from its part, controls execution by each power unit of the obtained assignment and transmit the information necessary for execution of this assignment to a top level – the MC ALFCS of the IPS of Ukraine. In order to ensure efficient control of power units, the master controller of ALFCS of the IPS of Ukraine receives from PPCS the necessary telemetering data and telesignals arriving from the TPP telemetry equipment. Organization of PPCS communication with the dispatch center (DC) of the regional PS of NPC «Ukrenergo» provides for transmission of necessary volume of data from PPCS , telemetry and telesignals to the dispatch center, and also data on participation of the power units in load-frequency control in the IPS of Ukraine and the execution of assignments received by them from the MC ALFCS of the IPS of Ukraine. Provision is made for possibility to organize the PPCS communication with the informational dispatch center of generating company, to which TPP is subordinate, if a creation of such a center is provided.
 
Providing the necessary background information to TPP employees is carried out by means of PPCS communication with the local computer network of the TPP. In order to ensure protection of industrial management network against unauthorized access, the demilitarized protective zone (DPZ) is created between a PPCS network and the local area network (LAN) of the power plant.
 
In order to ensure rendering of maintenance services, developer of the PPCS software and hardware complex envisages a possibility of creating a remote access to the system.

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