A method for estimating a frequency of an electrical signal at a node in an electrical system having a plurality of nodes (114, 115, 116, 117, 118, 119, 120, 200), the method comprising: determining, at a node of an electrical system having a plurality of nodes, at least one property of an electrical signal at the node at a current instant in time; determining a previous function indicative of one or more properties of the electrical signal at the node at a previous instant in time; determining a function of an error in a previous frequency estimation at the node at a previous instant in time; determining a current function indicative of the one or more properties of the electrical signal at the node at the current instant in time in accordance with the at least one determined property of the electrical signal at the node at the current instant in time, the previous function indicative of the one or more properties of the electrical signal at the node at a previous instant in time, and the function of the error in the previous frequency estimation; receiving, from at least one other node of the plurality of nodes, a current function indicative of one or more properties of an electrical signal at the at least one other node at the current instant in time; combining the current function indicative of one or more properties of the electrical signal at the node and the current function indicative of one or more properties of the electrical signal at the at least one other node to produce a current combined function indicative of one or more properties of the electrical signal at the node at the current instant in time; and estimating a current frequency of the electrical signal at the node in accordance with the current combined function. determining, at a node of an electrical system having a plurality of nodes, at least one property of an electrical signal at the node at a current instant in time; determining a previous function indicative of one or more properties of the electrical signal at the node at a previous instant in time; determining a function of an error in a previous frequency estimation at the node at a previous instant in time; determining a current function indicative of the one or more properties of the electrical signal at the node at the current instant in time in accordance with the at least one determined property of the electrical signal at the node at the current instant in time, the previous function indicative of the one or more properties of the electrical signal at the node at a previous instant in time, and the function of the error in the previous frequency estimation; receiving, from at least one other node of the plurality of nodes, a current function indicative of one or more properties of an electrical signal at the at least one other node at the current instant in time; combining the current function indicative of one or more properties of the electrical signal at the node and the current function indicative of one or more properties of the electrical signal at the at least one other node to produce a current combined function indicative of one or more properties of the electrical signal at the node at the current instant in time; and estimating a current frequency of the electrical signal at the node in accordance with the current combined function.