TOPOLOGICAL INTERLOCKING OF OPERATIONAL SWITCHING

TOPOLOGICAL INTERLOCKING OF OPERATIONAL SWITCHING

I. A. Golovinskii,1 M. Yu. D’yachenko,2 M. I. Londer,3 and A. V. Tumakov3

Translated from Gidrotekhnicheskoe Stroitel’svo, No. 7, July 2018, pp. 29 – 37.

Positions of interconnected switching devices determine the topological interlocks of switching operations at

substations. The paper reviews two approaches for implementing programmable topological interlocks:

offline and online. The paper highlights the disadvantages of offline and flexibility of online solutions. A new

object-topology approach to modeling of electrical networks is described. It allows applying the standard rules

of topological interlocking automatically, both offline and online. An example of such automation is provided.

Keywords: operational dispatch management; switching control; interlocking of switching operations; topo-

logical interlocking; digital substation; switching diagram topology analysis; object-topology approach.

Interlocking of operational switching at substations is

one of the most important means of ensuring reliability,

safety and accident-free real-time control of electrical net-

works. Interlocking prevents operations, which can cause ac-

cidents or lead to a dangerous decrease in reliability of the

electrical network operating mode, as well as result in health

problems in people.

Most often, to interlock an operation means to eliminate

a physical possibility of performing such operation, which is

achieved by activating a special interlocking device. Such in-

terlocking devices can be called hardware or automatic inter-

locks.

At the same time, the technology of operational switch-

ing within electrical networks imposes a number of prohibi-

tive rules, which are not implemented in the hardware. These

rules are listed in the regulatory technical documents con-

cerning real-time operations control [1 – 5]. They are exe-

cuted by the operating and dispatching personnel when mak-

ing decisions on whether the considered operation can be al-

lowed. Such prohibitive rules are called logical interlocks.

Based on the technological content, interlocks can be di-

vided into switching and performance interlocks. The former

are defined by the position of the interconnected switching

devices (SD) and circuit configuration, and can also be re-

ferred to as topological. The latter depend on the electrical

mode parameters.

The interlocking requirements for SD switching opera-

tions, which are defined by standard switching procedures

and standards, are not tied to specific substation devices.

They are of generalized nature. These are the standard in-

terlocking rules. Along with them, individual interlocking

rules are used, which are related to specific devices. An indi-

vidual interlocking rule can be a logical customization of a

standard rule, but can also be introduced independently of

the standard rules to supplement them as dictated by the local

conditions.

When applied to a specific switching operation, the stan-

dard interlocking rule is subject to customization. It repre-

sents a logical conclusion of the individual interlocking rule

after it has been customized from the standard rule. This con-

clusion can be derived mentally by a person, or logically by a

logic device.

Hardware (automatic) interlocks in principle are more re-

liable than logical. Ideally, all interlocks acting as logical

should be implemented as hardware. Currently, the hardware

implementation of interlocks means that they have to be pro-

grammed into controllers and computers.

Offline and online solutions for interlocking switch-

ing operations. There are two approaches to algorithmiza-

tion of the solutions related to interlocking of operations:

offline and online. When using an offline approach, the inter-

locking solution is not generated at the moment when it is re-

quired, once the switching command is issued, but ahead of

time. For each operation subject to control, all actual combi-

nations of switching and other device conditions should be

considered in advance. For each such combination, a de-

cision of whether to allow or deny an operation is selected.

The decision is saved in the controller or computer memory.

To configure and store a variety of such decisions, special

decision tables are used [6]. When the personnel enters a

command for operational switching, a ready interlocking

Power Technology and Engineering Vol. 52, No. 5, January, 2019

605

1570-145X�19�5205-0605 © 2019 Springer Science+Business Media, LLC

1 North-Caucasus Federal University, Stavropol, Russia;

[email protected].

2 JSC “IMPEDANCE”, Stavropol Territory, Kislovodsk, Russia.

3 JSC “IMPEDANCE”, Moscow, Russia.

DOI 10.1007/s10749-019-01000-4

decision is automatically retrieved from the decision table

and executed.

Traditional hardware interlocks (mechanical, electrome-

chanical, electromagnetic) represent one type of offline inter-

locks.

When utilizing an online approach, interlocking decision

are not generated in advance. Situation analysis and decision

making are conducted upon entering commands by the per-

sonnel. In case of topological interlocks, decision making co-

mes down to analyzing a current circuit configuration graph.

Each of the two approaches have their own advantages

determining which one of them is the most preferable for a

specific situation. For topological interlocks, an offline ap-

proach is useful when the number of interlocking or permit-

ting configurations of the circuit is low.

Let us use a very simple example to analyze offline inter-

locking of closing an earthing switch depending on the posi-

tion of two adjacent disconnectors (Fig. 1a). In this example,

a number of options, which must be considered in order

to completely describe all the interlocking decisions, is equal

to four. This is determined by the fact that each disconnector

can be in one of the following two positions — “closed” or

“open.” In order to implement such interlocking in a pro-

grammable controller, it makes sense to create a one-time

description of these four options and save it in the form of

a decision table (Fig. 1b). All possible combinations of the

D1 and D2 positions are shown in the first two lines of the

decision table. These are the “controlling” elements. The

open disconnector position is designated as 0, and closed po-

sition — as 1. In the third line, symbol “+” indicates a per-

mission to close an open earthing switch ES, and symbol “–”

indicates that such opening is prohibited. Here, ES represents

a “controlled” element.

A decision table for interlocking switching operations of

a switching device (controlled element) is configured in a

similar manner for any switching diagram containing any

number of controlling elements subject to switching. As-

suming that N is the number of controlling elements subject

to switching on the diagram, the complete decision table for

interlocking a controlled element should contain N + 2 rows

and 2N + 1 columns. The first column contains the element

names. All columns, except for the first one, will contain

in the first N lines different combinations of the positions

of the controlling elements. For each such combination, the

last two elements in the column will express the interlocking

decisions with respect to opening and closing of the con-

trolled element. Symbol “+” will indicate a permission to

switch, and symbol “–” will indicate that such switching

is prohibited.

A decision table can be created only for the “opening”

operation with respect to controlled SD (as shown in the ex-

ample in Fig. 1b), or just for the “turning off” operation. In

this case, it will contain N + 1 lines, and only the last line

will contain the decision symbols (“+” and “–”). In such ta-

ble, it is enough to show only those columns which represent

switching permission options, i.e. contain the “+” sign in the

last line. Then, any missing combination of the controlling

element positions will be interpreted as prohibitive. Or vice

versa, it is possible to show only prohibiting combinations in

the table, in which case the missing combinations will imply

a permission to switch. A method containing the lesser num-

ber of combinations is considered more favorable.

If the number of permitting and prohibiting combinations

in the decision table is equally high, the use of such Table is

unproductive. Another major disadvantage of the decision ta-

bles is their lack of transferability and invariance relative to

the circuit topology. Generally speaking, one standard inter-

locking rule produces different decision tables for different

circuits. For example, the standard interlocking rule for clos-

ing a busbar earthing switch in absence of the visible circuit

breaking by open disconnectors produces a decision table for

busbar BB1 of the switchgear (Fig. 2), which cannot be ap-

plied to any other switchgear. Such disadvantage of the deci-

sion tables cannot be eliminated in principle.

But the decision tables simply represent a way to record

the offline interlock-related decisions. Therefore, the appli-

cability of the offline approach is not universal.

The online approach is free of the disadvantages typical

for offline approach, however its implementation requires a

special mathematical tool to analyze the topology of the

switching diagrams. Such tool is equally suitable for both,

online topological interlocking and automated creation of the

offline decision tables relative to topological interlocking.

Developments in the field of topological interlocking.

The requirements concerning implementation of operational

interlocking in programmable controllers are stated in the

document entitled “Operational interlocking organization

procedure at new generation substations” [2]. Specifically, it

is established that permission of the switching operation of a

switching device must be generated “by using logic algo-

rithms programmed into controllers according to the logic of

conventional relay-contact circuits” (clause 3.1.6.1).

Majority of the programmable interlock developers com-

ply with this requirement by utilizing a computer simulation

of relay-contact circuits [7, 8]. Using of LD (Ladder Dia-

gram) programming language helps realizing this approach.

This is a graphic language of the relay-contact circuits em-

bodied in the form of “ladders” enclosed one into another.

Same as the decision tables, interlocking programs in LD

606 I. A. Golovinskii et al.

P1P1

P2

P2

ES

ES

a

b

Fig. 1. Connection between earthing switch and two disconnectors

(a) and decision table for interlocking the opening of the earthing

switch (b).

language are not invariant relative to circuit topology. The

decision tables are mathematically based on Boolean alge-

bra, and LD programs — on the theory of relay-contact cir-

cuits. The fundamentals of these methods were developed in

the second half of the 1930s by A. Nakashima, K. E. Shan-

non and V. I. Shestakov [9]. Boolean algebra was applied to

creating contact circuits of hardware interlocks for the first

time in 1940 by an engineer from Leningrad V. A. Rosenberg

[10].

It is possible to overcome the disadvantages of the above

approaches only by using the methods directly operating the

circuit topology of electrical networks and substations. The

first topological method for analyzing contact circuits was

developed in the second half of the 1940s at the Leningrad

Electrotechnical Institute (LETI) by B. I. Aranovich and A.

G. Lunts [11 – 15]. This method utilized the algebra of

Boolean matrices as its mathematical tool. However, this

method did not find application in electrical network opera-

tions control systems.

Standard topological interlocks were implemented for

the first time in the operational switching simulator devel-

oped in the 1980s at the All-Union Electric Power Research

Institute (VNIIE) [16]. For this purpose, a query language of

the graph-type database management system was used.

Revealing a mathematical structure of the graph analysis

algorithms used in the simulator led to the development of

algebraic methods of analyzing circuit topology, including

those for interlocking solutions [17 – 19]. A special algebra

of graphs was developed, which is briefly described below.

Based on its software implementation, topological interlock-

ing of operational switching was developed by DECIMA in

the form of SCADA�EMS KOTMI-14 software package

[20].

Figure 3 shows a portion of the tested electrical network

diagram (green — 500 kV equipment, red — 220 kV equip-

ment, blue — 110 kV equipment; closed switches are filled

with green, and open switches are filled with red).

The topological interlocking KOTMI-14 software ana-

lyzes the incoming command to open the switch S-10 at the

Zapadnaya substation (SS). This switch is marked with

dashed red contour. Prior to this, switch S-11 was opened at

the Zapadnaya substation. The diagram displays the message

generated by the situation analysis program.

The program has checked the interlocking rules designed

to prevent the following three technological faults, which

may occur as a result of switch opening:

— consumer blackout;

— disturbance of (auto)transformer switching sequence;

— top-down network division based on the voltage rat-

ings.

The program has detected that the first technological

fault does not occur: none of the network nodes lose voltage

as a result of opening switch S-10. The second fault does not

occur either: transformers at Zapadnaya substation (voltage

fed from the lower-voltage side) do not lose voltage from the

higher-voltage side upon opening switch S-10. Only the third

of the possible faults is detected: in case of opening switch

S-11, the connection between Zapadnaya substation and

Prirechnaya State District Power Plant (SDPP) will be inter-

rupted along the 500 kV line, while the connection between

them via a 220 kV network through Petrovskaya and Velinka

substations will still remain. As can be seen from Fig. 3,

Topological Interlocking of Operational Switching 607

TVr1

VTrD1

ES1

BBD11

BBS1 220 kV

BBD12 BBD13

BBS2 220 kV

BBSD1

BBD14 BBD15

Fig. 2. Example of a switchgear diagram illustrating topological interlocking.

there is an additional bypass of the part of the 220 kV net-

work via a 110 kV network through Tsentralnaya substation,

Central Heating and Power Plant CHPP-1 and Osinskaya

substation. This configuration is dangerous in the way that

the total capacity of the lines rated for voltage below 500 kV

can be insufficient for providing a power overflow from

Prirechnaya SDPP to Zapadnaya substation.

Object-topology modeling of electrical network. In or-

der to model and analyze the electrical circuits in KOTMI-14

software package, a new conceptual approach was used. It is

based on the synthesis of object-oriented modeling and to-

pology processor [21].

An object-oriented model of the subject domain, such as

electrical network, is created. Objects of this model form a

system of classes. Object associations represent binary rela-

tions between the classes. Then, a non-oriented graph is cre-

ated, the vertices of which represent one-to-one model

objects, while edges represent associations between the ob-

jects (Fig. 4). This graph is subject to analysis by means of

the topology processor.

Such model of subject domain is called a graph-object

or object-topology model, or also an “objects-associations”

model. We call the system of methodical, mathematical and

software tools, used to create and analyze such model, a

graph-object simulation.

If subject domain is an electrical network, then the ob-

ject-oriented model of its detailed switching diagram can be

created, for example, by using CIM (Common Information

Model) class objects. Developing interlocking solutions gen-

erally requires analysis of the condition of the detailed


Fig. 3. Automatic detection of dangerous operation in SCADA�EMS KOTMI-14: top-down division of network upon switch opening.

switching diagram considering the position of all SDs. The

object-topology model required for this purpose is created

based on the CIM profile formed by the following classes:

ConductingEquipment — main current-conducting de-

vices of the electrical network: power lines, power trans-

formers, sections of busbars, shunt reactors, switches,

disconnectors, etc.;

ConnectivityNode — connection points between adja-

cent devices;

Terminal — device connection points; these are used to

describe relations between objects of the ConnectivityNode

and ConductingEquipment classes.

Definitions of these classes are provided by the standard

in [22].

Figure 5 shows a fragment of the object-topology model

of the detailed switching diagram created from the objects of

these classes. The left column on this diagram is occupied by

the ConductingEquipment class objects. This class is basic

for a number of the specialized subclasses describing spe-

cific types of current-conducting devices. When implement-

ing a specific model, such devices must be described as ob-

jects of such specialized subclasses: switch — as a Breaker

class object, disconnector — as a Disconnector class object,

transformer — as a PowerTransformer class object, etc.

Each object of the Terminal class is related by means of

associations with one object of the ConductingEquipment

class, and one object of the ConnectivityNode class.

The diagram analysis for topological interlocking is of-

ten limited by the boundaries of a substation or even switch-

gear. In case of the interlocks used in case of the power line

switching, the analysis involves two substations connected

by this power line. When interlocking the switching opera-

tion of switches, the analysis can cover an extensive portion

of the electrical network. In this case, for simplification pur-

poses, instead of detailed switching model, a generalized one

should be used. For example, a graph portion of the model

intended for calculating electrical modes can be used.

Calculation of sets and graphs in object-topology

model. Solution of the majority of problems associated with

topological analysis of electrical circuits can be centered

around a set of a small number of operations with graphs.

When applying a standard rule of topological interlocking, it

needs to be customized. Such customization usually comes

down to combining the following operations with non-ori-

ented graphs:

A + B — union of graphs A and B;

A& B — intersection of graphs A and B;

A – B — difference of graphs A and B;

A * B — increment of graph A by graph B;

A ^ B — closure of graph A by graph B. (1)

Operation A ^ B is defined as a union of graph A with all

connected components of graph B having a nonempty inter-

section with graph A. This operation allows calculating the

“distant” electrical connections between the circuit nodes.

To calculate the “close” connections, operation A * B is used.

Its definition is as follows: graph A * B is a union of a

non-oriented graph A with all those edges of a non-oriented

graph B, in which at least one end belongs to graph A. Spe-

cifically, a union of graph A with edge e is understood as a

union of graph A with the graph actually consisting of the

edge e and two of its ends.

The result of performing each of the operations (1) is

again a non-oriented graph. Due to this, operations can be

combined, while composing formulas of different complex-

ity. As a result, topological interlocking solutions come

down to calculating graphs.


Ob

je

ct

s

Ob

je

ct

s

Associations

Associations

Associations

Class P Class Q Class ... Class X

Fig. 4. Object-topology model of subject domain.

Switch

Disconnector

Transformer

Fig. 5. Fragment of the detailed object-topology model of the elec-

trical network based on CIM classes.

Symbols of the basic operations (1) were chosen based

on the fact that they can be “re-loaded” (re-defined) in C++

programming language. This, perhaps, is the easiest way to

program them. Decima has developed a library of programs

performing operations (1) [23].

The use of operations (1) allows concisely expressing the

solution of, for example, the following problem. Let S repre-

sent a set of graph nodes of the diagram, which represent the

sources, and let P represent a set of nodes, which represent

consumers. Find the set of consumers under voltage. The tar-

get set is expressed by the formula:

(S ^ G) & P. (2)

Figure 6 shows the example of graph G, part of the verti-

ces of which constitutes a set of sources S (red circles), and

another part constitutes a set of consumers P (blue circles).

Graph G contains a marked subgraph S ^^ G (its edges and

also vertices not belonging to sets S and P are shown in red);

and the remaining edges and vertices of graph G not belong-

ing to sets S and P are shown in black. Subgraph S ^^ G rep-

resents a union of those connected components of graph G,

which contain at least one vertex from set S. These compo-

nents include those and only those vertices contained by the

set of consumers P, which are connected with the sources.

The set of such consumers is expressed by formula (2).

Example of using a graph-object approach to algo-

rithmization of standard topological interlocking. The ac-

tion logic of the operational interlocking of switching opera-

tions relative to switching devices is strictly defined by the

regulatory technical documents. The completeness and clar-

ity of these requirements provide basis for attempting to au-

tomate the creation of the interlocking algorithms of SD

switching based on the given primary circuit diagrams. This

problem is formulated, for example, in [24]. Approaches to

solving this problem are suggested in [7, 8]. However, an ex-

haustive procedure for finding a solution of this problem was

already published in [17, 18]. It is based on the described al-

gebra of graphs, which allows creating algorithms that are in-

dependent on the topology of the primary circuit diagrams.

Size restrictions of the paper prevent us from demon-

strating all the possibilities of graph-object calculations for

algorithmization of topological interlocking with the due

completeness. Let us provide just a single example of finding

an interlocking solution, which is invariant with respect to

the diagram topology. It can be applied both offline, and

online.

Let us consider a problem of interlocking the opening of

an earthing switch while the disconnectors connected to it

are in the closed position. Standard interlocking rules pro-

hibit the closing of the earthing knives (if it is not intended

for grounding a neutral) within the section of the circuit,

which is not isolated by the open disconnectors from all di-

rections, from where the voltage can be supplied [2 – 5]. The

circle of open disconnectors forms a “visible break” around

the grounded section.

We will explain the solution by using earthing switch

ES1 as an example in the switchgear circuit (Fig. 2). In this

switchgear, the voltage can be supplied to ES1 from the

220 kV busbar system BBS1, as well as the voltage trans-

former VTr1, if it is not disconnected from the secondary cir-

cuit side. To create a visible break around ES1, it is necessary

to open the following elements: busbar disconnectors

BBD11, BBD12, BBD13, BBD14, BBD15; disconnector of

the busbar connecting switch BBSD1; and also a disconnec-

tor of the voltage transformer VTrD1.

A detailed object-topology model of the switchgear

shown in Fig. 2 needs to be created.

For this purpose, we will be using CIM classes. Let us

denote the graph of this model as G. The vertices of this

graph will represent the objects of the CIM classes, and the

edges will represent the associations between the objects.

Figure 7 shows a fragment of this graph-object model. It

contains the object ES1 and other objects associated with it,

which must be considered in the interlocking solution related

to opening ES1.


Fig. 6. Finding consumers connected with sources.

VTrD1

ES1

ES1

BBS1 220 kV

BBSD1

BBD1

BBD2

BBD3

BBD4

BBD5

Fig. 7. Object-topography model of the connection between

earthing switch ES1, disconnectors and busbar system in the switch-

gear diagram shown in Fig. 2.

The vertices of graph G represent the objects of CIM

classes shown in the form of blocks. The same color blocks

represent the objects related to the same CIM class. Classes

Disconnector, GroundDisconnector, BusbarSection, and

Ground are subclasses of the class ConductingEquipment.

Green circles represent the Terminal class objects. The

dashed lines show associations between the objects belong-

ing to the shown fragment and the objects outside of it. Fig-

ure 8a shows this graph in more compact form.

If the substation equipment and device connections are

described in the relational database, it becomes possible to

retrieve the sets of devices of a certain type, which exist at a

substation (busbar sections, power transformers, switches,

disconnectors, etc.) by means of inquiries compiled using

SQL language. This does not contradict the use of the CIM

model.

Let us find in the database a set of all disconnectors of

the considered switchgear. Let D represent the set of all verti-

ces of graph G representing disconnectors. Let us also desig-

nate the vertex of graph G representing a given earthing

switch ES1 as z.

The vertices of graph G representing disconnectors,

which must be opened, form a ring around vertex z. We need

to find this ring. It can be easily calculated by using graph

operations (1).

Let us subtract set D from graph G. Figure 8b shows the

result of subtracting set D (as a graph) from graph G. When

subtracting a vertex, all graph edges, which are incidental to-

wards this vertex, are removed.

Graph G – D represents a set of portions of the substation

diagram, which are separated by disconnectors. Let us desig-

nate the portion that contains vertex z (ES1) as S. It is shown

in Fig. 8c and can be expressed by the formula:

S = z ^ (G – D).

The increment operation S * G adds to graph S all the

edges of graph G, in which at least one end belongs to graph

S. The result of this operation is shown in Fig. 8d. A ring of

disconnectors has been added to graph S, which isolates S

from the remaining portion of graph G. Let us designate this

ring as R. It represents a set of disconnectors that we had to

find. This ring can be obtained by subtracting graph S from

graph S * G:

R = (S * G) – S.

The result of this subtraction is shown in Fig. 8e.

Although for illustration of the described algorithm we

used the switchgear diagram shown in Fig. 2, we did not use

in the algorithm any topological features of this diagram dis-

tinguishing it from other switchgear diagrams. The algorithm

is applicable not only to busbar earthing switches, but gener-

ally to any switches. The only condition associated with the

specifics of the diagram is that graph G must invariably in-

clude all disconnectors having an effect on interlocking the

opening of this earthing switch. If this is not a power line

earthing switch, then it is sufficient for graph G to only rep-

resent the switchgear, to which this earthing switch belongs.

Otherwise, graph G must contain a power line and both

switchgears at two substations, which are connected by this

power line. Accordingly, D should then denote the set of all

disconnectors at both substations.

The described simple graph calculations can be per-

formed either offline, or online. In both cases, they provide a

customized interlocking rule, which lists all disconnectors

which must be opened to provide a visible break. In the

offline mode, these calculations are only performed once for

each earthing switch, and the obtained customized rule is

saved to the knowledge base. On the other hand, the online

calculation are performed every time when exercising con-

trol of a command for closing of any earthing switch.

Readers familiar with the conventional methods of pro-

gramming the switching interlocks, can easily see how much

simpler the proposed method of graph calculations is. Other

standard rules of topological interlocking may require more

complex calculations. But regardless, this approach certainly

provides more simple algorithms compared to the conven-

tionally used methods of Boolean algebra and relay-contact

circuits.

CONCLUSIONS

1. Operational switching interlocks in the electrical net-

works should include not only the hardware (automatic) in-

terlocks, but also the rules prohibiting switching operations


BBD11

BBD11

BBD11

BBD12

BBD12

BBD12

BBD13

BBD13

BBD13

BBD14

BBD14

BBD14

BBD15

BBD15

BBD15

VTrD1

VTrD1

VTrD1

ES1

ES1

ES1

ES1

BBS1

BBS1

BBS1

BBS1

BBSD1

BBSD1

BBSD1

a b

c

d

e

Fig. 8. Graph calculations when interlocking the opening of the

earthing switch.

of the switching devices, which result from the requirements

of the regulatory technical documents concerning real-time

operations control. These standard interlocking rules are not

associated with any specific equipment and must be custom-

ized when applied to a switching device subject to switching.

2. Topological interlocks are defined by the condition of

the interconnected switching devices. In this paper, two ap-

proaches for implementing the standard topological inter-

locks are considered — offline and online. When offline ap-

proach is used, the interlocking decisions are generated one

time outside of the real-time control loop, then saved to the

memory of the control system and applied once the com-

mand for switching of a corresponding switching device is

issued. The online interlocking solutions are generated auto-

matically once the command for switching of a correspond-

ing switching device is received.

For certain standard rules of topological interlocking, the

offline implementation is either inefficient, or practically im-

possible. The offline approach cannot be applied at all times,

while the online approach is universal and is based on auto-

matic customization of the standard rules of topological in-

terlocking by analyzing the electrical network model.

3. The implementation of programmable controllers at

substations and transitioning to programmable interlocks

have expanded the capabilities of hardware interlocking

quite significantly. However, in practice, stereotypic ap-

proaches are still being used during the design process,

which are based on decision tables or simulation of the re-

lay-contact circuits. Such methods have certain disadvan-

tages, including the need for sorting through all possible

combinations of SD positions, as well as general inability to

transfer interlocking algorithms from one diagram to another

having a different topology.

4. This paper describes the topological interlocking

algorithmization procedure based on a new simulation

method associated with the object-topology (graph-object)

approach. The latter consists in analyzing the topology of the

graphs describing the structure of the object-oriented model

of subject domain. The object-topology approach allows

overcoming the disadvantages of the conventional methods

of topological interlock programming. The typical interlock-

ing solution algorithms, resulting from using such approach,

are independent of the specific topological features of a spe-

cific substation. They are equally applicable offline and on-

line. The paper offers an example of such algorithm.

5. The object-topology approach provides a natural for-

malization of the standard topological interlocking. In the

object-topology model, images of the diagrams mentally

navigated by a person are replaced with corresponding

graphs, and verbal definitions of the switching configura-

tions are replaced with mathematical formulas. Based on

these formulas, switching characteristics of the circuits are

calculated, which determine the interlocking solutions. As a

result, logical reasoning performed by a person when making

interlock-related decisions is replaced by calculating graphs.

6. With regards to the simulated switching modes, such

as testing the switching formats and automated simula-

tor-based control of operating and dispatching personnel, in-

terlocking is carried out by using computer models of electri-

cal networks. The object-topology approach allows for a sig-

nificant reduction in simulation costs due to the use of

mathematical models of standard interlocking. As a result, a

labor-consuming process of creating a number of individual

interlocking models is eliminated.

7. The object-topology approach is in-line with the CIM

principles and complies with the IEC 61968 and IEC 61970

standards. It was used to implement topological interlocking

into the SCADA�EMS KOTMI-14 software package. The

practical experience provides evidence showing that the ap-

plication of such approach simplifies the development of

topological interlocking and improves its reliability.

REFERENCES

1. RD 34.35.512. Instructions for Operating Real-Time Safety In-

terlocks in High-Voltage Electrical Switchgear [in Russian], ap-

proved by the USSR Ministry of Energy on October 05, 1979.

2. Operational Interlocking Organization Procedure at New Gen-

eration Substations [in Russian], approved by the Limited Lia-

bility Federal Grid Company of Unified Energy System (FGC

UES, LLC) on May 05, 2010, No. 236 r.

3. State Standard GOST R 55608–2013. Unified power system and

isolated power systems. Operational dispatch management.

Switching at electrical installations. General requirements [in

Russian], Moscow (2014).

4. SO 153-34.20.505–2003. Instructions for Switching at Electri-

cal Installations [in Russian], NTs ÉNAS Publishing, Moscow

(2004).

5. Rules on Labor Safety when Operating Electrical Installations

(POTEU) [in Russian], approved by order No. 328n of the Min-

istry of Labor and Social Protection of the Russian Federation

dated July 24, 2013; effective date: August 04, 2014.

6. E. Humby, Programs from Decision Tables [Russian transla-

tion], Mir, Moscow (1976).

7. A. V. Trofimov, A. M. Polyakov, G. A. Abdukhalilov, and

R. A. Gorbunov, “Generating operational interlocking algo-

rithms based on the information models of single-line diagrams

of electrical installations,” Élektr. Stantsii, No. 7(1008), 2 – 5

(2015).

8. G. A. Abdukhalilov, Development of the Computer-Aided Pro-

cedure for Designing an Operational Interlocking of Digital

Substations. Candidate’s Thesis [in Russian], MÉI, Moscow

(2017).

9. V. I. Levin and B. V. Biryukov, “Another look at the history of

discovering logical modeling of the technical devices,” Vestn.

Mosk. Univ. Ser. 7. Filos., No. 1, 37 – 52 (2009).

10. V. A. Rosenberg, “Interlocking problem and contact groups

transformation,” Avtomat. Telemekh., No. 1, 47 – 54 (1940).

11. B. I. Aranovich, Matrix Methods of Analysis and Synthesis of

Contact-Relay Circuits. Candidate’s Thesis [in Russian], LÉTI,

Leningrad (1947).

12. B. I. Aranovich, “Utilization of matrix methods in the aspects of

structural analysis of contact-relay circuits,” Avtomat. Tele-

mekh., 10(6), 437 – 451 (1949).


13. A. G. Lunts, “Application of matrix Boolean algebra to analysis

and synthesis of contact-relay circuits,” Dokl. AN SSSR, 70(3),

421 – 423 (1950).

14. A. G. Lunts, “Synthesis and analysis of contact-relay circuits by

means of characteristic functions,”Dokl. AN SSSR, 75(2), 201 –

204 (1950).

15. A. G. Lunts, “Algebraic methods of analysis and synthesis of

contact circuits,” Izv. AN SSSR. Ser. Matem., 16(5), 405 – 426

(1952).

16. Yu. Ya. Kupershmidt, Yu. Ya. Lyubarskii, and V. G. Ornov,

“Principles of developing a universal programmable switching

training simulator,” Élektr. Stantsii, No. 11, 48 – 52 (1982).

17. I. A. Golovinskii, “Object-oriented approach to developing pro-

grams for analyzing switching diagrams of electrical networks,”

Izv. RAN. Énerget., No. 2, 46 – 56 (2001).

18. I. A. Golovinskii, “Methods of analyzing topology of switching

diagrams of electrical networks,” Élektrichestvo, No. 3, 10 – 18

(2005).

19. I. A. Golovinskii, “Logic and topology of switchover interlocks

in electrical networks,” Int. J. Appl. Eng. Res., 11(3), 2007 –

2015 (2016), http:��www.ripublication.com�ijaer16�ijaerv11n3_69.pdf.

20. Platform for solving power engineering problems KOTMI-14,

DECIMA, http:��www.decima.ru�upload�iblock�a4f�kotmi_14.pdf.

21. I. A. Golovinskii, “Topological object-association model for

simulating electrical networks,” Int. J. Appl. Eng. Res., 11(12),

7857 – 7867 (2016), http:��www.ripublication.com�ijaer16�ijaerv11n12_44.pdf.

22. IEC 61970-301. Energy management system application pro-

gram interface (EMS-API), Part 301. Common information

model (CIM) base.

23. Certificate of State Registration of Computer Software

No. 2011613357, A. V. Tumakov, I. A. Golovinskii, M. I. Lon-

der, and M. Yu. Dyachenko, Universal topological processor

for electrical network intellectual management systems

(UNITOP) [in Russian], registration date April 29, 2011.

24. A. A. Usitvina, Study of the Operational Safety Interlocking

Systems at Energy Facilities with Voltage Exceeding 1 kV to Im-

prove Power Safety and Efficiency. Candidate’s Thesis [in Rus-

sian], MÉI, Moscow (2014).


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TOPOLOGICAL INTERLOCKING OF OPERATIONAL SWITCHING