Topogrid

Package topogrid contains implementations of basic power grid algorithms based on the grid topology. We use three main things - node, edge and equipment. Each power equipment can be represented as a topological node or edge. The wonderful library is used to represent the graph.

List of terms and abbreviations

• Edge: A link between two nodes. From the point of view of electrical network equipment, edge can imagine circuit breakers, disconnectors, power transformers, earthing switches, etc. All electrical network equipment with more than one terminal.
• Node: The name for any single junction. Nodes are connected to one another by edges. E.g. power supply, DERs, Consumer transformer substations, ground (earth) etc.
• Terminal: The endpoint of a power grid equipment, represented by node.

Distribution grid example

• FSW - feeder switch
• REC - recloser (Automatic circuit breaker with reclosing function)
• DS - disconnect switch
• TS - transformer substation (consumer)
• SW - switch (SW10 - bus coupler circuit breaker)

Graph example

Database

The power system topology is stored in the database as a set of tables.

Usage

type EquipmentStruct struct {
	id              int
	typeId          int
	name            string
	electricalState uint8
	poweredBy       map[int]int64
	switchState     int
}

type NodeStruct struct {
	idx             int
	id              int
	equipmentId     int
	electricalState uint8
}

type TerminalStruct struct {
	node1Id          int
	node2Id          int
	numberOfSwitches int64
}

type EdgeStruct struct {
	idx         int
	id          int
	equipmentId int
	terminal    TerminalStruct
}

topology := topogrid.New(len(nodes))

for _, node := range nodes {
  topology.AddNode(node.Id, 
    node.EquipmentId, 
    node.EquipmentTypeId, 
    node.EquipmentName)
}

for _, edge := range edges {
  err := topology.AddEdge(edge.Id, 
    edge.Terminal1, 
    edge.Terminal2, 
    edge.StateNormal, 
    edge.EquipmentId, 
    edge.EquipmentTypeId, 
    edge.EquipmentName)
  if err != nil {
    log.Errorf("%v", err)
  }
}

EquipmentNameByEquipmentId

Returns a string with node name from the equipment id

func (t *TopologyGridStruct) EquipmentNameByEquipmentId(equipmentId int) string

EquipmentNameByNodeIdx

Returns a string with node name from the node index

func (t *TopologyGridStruct) EquipmentNameByNodeIdx(idx int) string

EquipmentNameByNodeId

Returns a string with node name from the node id

func (t *TopologyGridStruct) EquipmentNameByNodeId(id int) string

EquipmentNameByNodeIdArray

Returns a string with node names separated by ',' from an array of node ids

func (t *TopologyGridStruct) EquipmentNameByNodeIdArray(idArray []int) string

EquipmentNameByEdgeIdx

Returns a string with node name from the node index

func (t *TopologyGridStruct) EquipmentNameByEdgeIdx(idx int) string

EquipmentNameByEdgeId

Returns a string with node name from the node id

func (t *TopologyGridStruct) EquipmentNameByEdgeId(id int) string

EquipmentNameByEdgeIdArray

Returns a string with node names separated by ',' from an array of node ids

func (t *TopologyGridStruct) EquipmentNameByEdgeIdArray(idArray []int) string

EquipmentIdByEdgeId

Returns equipment identifier by corresponded edge id

func (t *TopologyGridStruct) EquipmentIdByEdgeId(edgeId int) (int, error)

SetSwitchStateByEquipmentId

Set switchState field and changes current topology graph

func (t *TopologyGridStruct) SetSwitchStateByEquipmentId(equipmentId int, switchState int) error

AddNode

Add node to grid topology

func (t *TopologyGridStruct) AddNode(id int, equipmentId int, equipmentTypeId int, equipmentName string)

AddEdge

Add edge to grid topology

func (t *TopologyGridStruct) AddEdge(id int, terminal1 int, terminal2 int, state int, equipmentId int, equipmentTypeId int, equipmentName string) error

NodeIsPoweredBy

Get an array of nodes id with the type of equipment "TypePower" from which the specified node is powered with the current 'switchState' (On/Off) of the circuit breakers

func (t *TopologyGridStruct) NodeIsPoweredBy(nodeId int) ([]int, error)

for _, node := range nodes {
  poweredBy, err := topology.NodeIsPoweredBy(node.Id)
    if err != nil {
      log.Errorf("%v", err)
    }
    log.Debugf("%d:%s <- %v:%s", node.Id, topology.EquipmentNameByNodeId(node.Id), poweredBy, topology.EquipmentNameByNodeIdArray(poweredBy))
}

NodeCanBePoweredBy

Get an array of nodes id with the type of equipment "Power", from which the specified node can be powered regardless of the current 'switchState' (On/Off) of the circuit breakers

func (t *TopologyGridStruct) NodeCanBePoweredBy(nodeId int) ([]int, error)

for _, node := range nodes {
  poweredBy, err := topology.NodeCanBePoweredBy(node.Id)
    if err != nil {
      log.Errorf("%v", err)
    }
    log.Debugf("%d:%s <- %v:%s", node.Id, topology.EquipmentNameByNodeId(node.Id), poweredBy, topology.EquipmentNameByNodeIdArray(poweredBy))
}

CircuitBreakersNextToNode

Get an array of IDs of circuit breakers next to the node. If we need to isolate some area of the electrical network, we need to find all circuit breakers near a node in that area.

func (t *TopologyGridStruct) GetCircuitBreakersEdgeIdsNextToNode(nodeId int) ([]int, error)

for _, node := range nodes {
  nextTo, err := topology.CircuitBreakersNextToNode(node.Id)
    if err != nil {
      log.Errorf("%v", err)
    }
    log.Debugf("%d:%s <- %v:%s", node.Id, topology.EquipmentNameByNodeId(node.Id), poweredBy, topology.EquipmentNameByNodeIdArray(nextTo))
}

BfsFromNodeId

Traverses current graph in breadth-first order starting at nodeStart

func (t *TopologyGridStruct) BfsFromNodeId(nodeIdStart int) []TerminalStruct 

GetAsGraphMl

Returns a string with a graph represented by the graph modeling language

func (t *TopologyGridStruct) GetAsGraphMl() string 

SetEquipmentElectricalState

Set electrical states for equipment. Use this method to set colors on your single line diagram (SLD).

// Equipment electrical states
const (
	StateIsolated    uint8 = 0x00
	StateEnergized   uint8 = 0x01
	StateGrounded    uint8 = 0x02
	StateOvercurrent uint8 = 0x04
	StateFault       uint8 = 0x08
)

func (t *TopologyGridStruct) SetEquipmentElectricalState()

CopyEquipmentSwitchState

Copy equipment switch state frim one topogrid object to this

func (t *TopologyGridStruct) CopyEquipmentSwitchState(from *TopologyGridStruct) error