ACS TP of substations, automation of transformer substations

Automated Process Control System (APCS) — a set of hardware and software designed to automate the management of process equipment.

Substation for automated process control system (APCS) — a system that includes both software and hardware complex (PTC) that solves various tasks of collection, processing, analysis, visualization, storage and transfer of technological information and automated control of the equipment substationand the corresponding actions of the staff for control and operational management of the technological processes of the substation, carried out in cooperation with the software and hardware complex.

Taking into account the complexity and responsibilities of various management functions, the creation of an AC substation TP is carried out in stages, starting with less complex and responsible ones: operational control, automatic regulation, relay protection.A fully completed substation control system is called an integrated substation control system.

The substation ACS includes the following functions:

Operational management — collection and primary processing of discrete and analog information, formation, updating, update of the database, registration of emergency situations and transient situations, fixing the fact and time of issuing control commands, accounting for electricity delivered to consumers, transferred to neighboring power systems or received from them, information for display and documentation for operating personnel, monitoring the current values ​​​​of mode parameters, determining the duration of permissible overloads of transformers and other equipment, monitoring the duration of operation of equipment in severe conditions (with overloads), voltage quality monitoring, monitoring the operation of transformers and other equipment, recording the condition of the equipment, determining the resource of transformers (for isolation and for electrodynamic influences) and switching equipment,

In addition, determining the service life of switches on transformer load switches, monitoring the condition of high-voltage insulation, analyzing emergency situations, monitoring and managing energy consumption, automatically compiling operational switching forms, monitoring the condition of the operating current network, monitoring and optimizing the operation of the compressor unit and the air supply system of breakers, monitoring the cooling of transformers, monitoring the state of the automatic fire extinguishing system, monitoring the switching equipment, determining the distance to the place of damage along the power line, automatic maintenance of the daily record, formation of telemeasurements and telesignals and their transmission to the control rooms of the upper levels of management, execution remote control teams switching devices and control devices, the organization of the necessary communication and control channels with dispatch points and operational field teams,

Automatic control — control of voltage and reactive power, control of the composition of working transformers (optimization of the number of working transformers according to the criterion of minimum losses of active power), load control in emergency modes, adaptive automatic closing and automatic transfer switch,

Relay protection - relay protection of all elements of the substation, diagnostics and testing of relay protection and automation, adaptation of relay protection, analysis of the operation of relay protection by signaling, excess of breaker failure.

The digital technology of the substation provides the following advantages:

• increasing the reliability of all control functions due to automatic system diagnostics and expanding the possibility of using the entire volume of initial information,

• improving control over the condition of substation equipment,

• reducing the redundancy of circuits and information required to provide a certain level of reliability,

• increasing the possibilities of credibility and correcting the initial information due to the presence of a sufficiently large amount of redundant information,

• increasing the amount of information that allows the management system to make more informed decisions, —

• the ability to implement adaptive relay protection and control systems,

• reducing the total cost of a set of technical controls,

• the possibility of using new progressive technical means (high-precision sensors, optical systems, etc.).

Almost all developments have in common the use of multi-computer distributed complexes based on the structures of local computer networks as the technical base of APCS from substations. Microprocessors included in these complexes perform various technological and auxiliary functions, including communication between the substation and the control room.

Substation control functions that are automated using microprocessor technology include:

• collection and processing of information,

• display and document information,

• control of measured values ​​outside established limits,

• transferring information to senior management,

• perform simple calculations,

• automatic control of substation equipment in normal mode.

The highest requirements for reliability and speed are imposed on devices for relay protection and emergency control. Damage to microprocessor systems when performing functions of relay protection and automation of emergency control should be practically excluded.

The dialogue system must provide communication with APCS to different users: operational personnel, for which the simplest, close to natural language of communication is used, specialists in the field of relay protection and automation in emergency situations, making settings, checking and changing of settings (more complex, specialized language for communication), computer scientists (the most difficult language). With the help of the automated process control system, the following is monitored: the state (on-off) of the operational equipment, the current values ​​of the values ​​compared to the established permissible limits, the operational capabilities of the control bodies (equipment for communication, relay protection and emergency control ), the permissible duration of overloading of transformers and power lines, the difference in the transformation ratios involved in the parallel operation of transformers.

Automatic control functions in normal mode include: voltage regulation on bus at a substation by changing the transformation ratios of transformers, switching capacitors on and off, operating switching according to a given program, blocking disconnectors, synchronizing, disconnecting one of the parallel operating transformers to reduce the total power losses in low load mode, automating the readings of reporting electricity meters.

Control functions of ACS TP of substations in emergency modes include relay protection of substation elements, CBRO, automatic reconnection of power lines, automatic transfer switch, disconnection and load recovery.With the help of a microcomputer, adaptive systems for automatic reclosing of power lines and busbars have been implemented, which provide: a variable time delay (pause without current), taking into account the severity of the previous short circuit, the selection of the element for supplying voltage to the substation buses, remaining de-energized (according to the minimum level of the short-circuit current in the event of a long-term damage, according to the maximum value of the residual voltage in the busbars of the substation from which voltage is supplied, etc.), changing the time delay, switching off the automatic reclosing in case of repeated power line faults caused by severe weather conditions, alternate closing of circuit breaker phases with a two- or three-phase short circuit to ground (first, the circuit breaker of one of the damaged phases closes, and then, in case of of successful automatic closing, the switches of the other two phases), thus reducing the severity of the emergency disturbance in case of unsuccessful automatic closing.